WORKS OF DR. H. W. SCHIMPF PUBLISHED BY ' JOHN WILEY & SONS. A Text-book of Volumetric Analysis With special reference to the Volumetric Processes of the Pharmacopoeia of the United States. De- signed for the use of Pharmacists and Pharmaceu- tical Students. Fourth edition, partly rewritten, rzmo, xxix 4- 522 pages. Cloth, $2.50 Essentials of Volumetric Analysis. An introduction to the subject adapted to the needs of Students of Pharmaceutical Chemistry, izmo, ix 4-227 pages, 38 figures. Cloth, $1.25. A Systematic Course of Qualitative Chemical " Atrafysis-oi-Inorganic and Qrganic Substances ' Z' 7 •• .* • ' < t" ' I With ESpl^h^to^y Notes.'-8vo' yii+156 pages. I 1 A SYSTEMATIC COURSE OB QUALITATIVE CHEMICAL ANALYSIS OF INORGANIC AND ORGANIC SUBSTANCES WITH EXPLANATORY NOTES HENRY W. SCHIMPF, Ph.G., M.D. vrU Professor of Analytical Chemistry in the Brooklyn College of Pharmacy. FIRST EDITION YORK JOHN WILEY & SONS London: CHAPMAN & HALL, Limited 1906 Copyright, 1906 BV HENRY W. SCHIMPF ROBERT DRUMMOND, PRINTER, NEW YORK Authority to use for comment the Pharma- copoeia of the United States of America, Eighth Decennial Revision, in this volume, has been granted by the Board of Trustees of the United States Pharmacopoeial Convention, which Board of Trust- ees is in no way responsible for the accuracy of any translations oj the official weights and measures or for any statements as to strength of official preparations. PREFACE. Authority to use for comment the Pharma- copoeia of the United States of America, Eighth Decennial Revision, in this volume, has been granted by the Board of Trustees of the United States Pbarmacopoeial Convention, which Board of Trust- ees is in no way responsible for the accuracy of any translations oj the official weights and measures or for any statements as to strength of official preparations. clature, and prepares the student for what follows. The second part describes the analytical reactions of the metals and acids of pharmaceutical interest, and includes schemes and tables for use in analytical work. The third part treats of the qualitative analytical reactions of organic substances, and includes tests for official alkaloids and synthetic compounds, as well as other organic sub- stances used in medicine; also schemes for the detection of III IV PREFACE. poisons, the analysis of urine, and an article on the prepa- ration of reagents. The final e is dropped from the names of halogens and binary compounds, but is retained in the case of the alkaloids so as to avoid confusing them with glucosides. Chemical equations are given for most of the reactions in the inorganic part and for many of the reactions of organic substances, as it is believed that they greatly assist in gaining a clearer insight into chemical action. The author has given credit in the text wherever due, and besides this he acknowledges his in- debtedness to the United States Pharmacopoeia, Eighth Decen- nial Revision, and to Prof. Elias H. Bartley and Dr. Joseph Mayer, for their contributionsand valued suggestions; and he especially expresses his thanks to Dr. I. V. Stanley Stanislaus for the considerable work he has done in the preparation of this book. H. W. S. New York City, N. Y., October, 1905. CONTENTS. PART I. PAGE Definitions and General Considerations 1 Notation, Classification, and Nomenclature of Elements and Organic Compounds 7 PART II. Identification and Separation of Inorganic Bases and Acids. 17 Introductory 17 The Systematic Analysis of a Chemical Substance, Simple or Compound 22 Heat Test 24 Sulfuric-acid Test 25 The Charcoal Test 26 Sodium-carbonate Test 26 The Hydrochloric-acid Test 27 Table for the Identification of the Metals 28 Chart for the Separation of the Metals: Group 1 30 Special Tests for Metals of Group 1 32 Chart for the Separation of Group II 35 Special Tests for Metals of Group II 40 Chart for the Separation of Group III 47 Special Tests for Metals of Group III 50 Chart for the Separation of Group IV 56 Special Tests for Metals of Group IV 57 V VI CONTENTS. PAGE Group V 59 Special Tests for Metals of Group V 61 Chart for the Separation of Insoluble Phosphates 64 Preparation of a Solution for Analysis in the Wet Way 65 Alloys and Hard Metals 67 Table Showing the Solubility of the More Commonly Occurring Salts 68 The Identification of Acids and Acidulous Radicals 69 Systematic Detection of the Acids in Solutions 70 Special Tests for Acids of Group 1 76 Special Tests for Acids of Group II 76 Special Tests for Acids of Group III 79 Special Tests for Acids of Group IV 81 Special Tests for Organic Acids 83 PART III. Qualitative analysis of Organic Substances 87 Behavior of Organic Substances with Immiscible Solvents 88 Behavior of Organic Substances with Fehling's Solution 90 A Systematic Scheme for the Identification of the Most Impor- tant Carbohydrates ' 91 Chart for the Detection of the More Common Organic Com- pounds of Pharmaceutical Interest 92 Class A. Division a. Liquids Miscible with Water 104 Methods for the Detection of Methyl Alcohol in Grain Alcohol, Pharmaceutical Preparations, Beverages, etc 105 Class A. Division b. Liquids not Miscible with Water. . 110 Class B Ill Scheme for theldentification of Acetanilide, Phenacetin, Quin- ine Sulfate 115 Professor E. H. Bartley's Scheme for the Identification of Or- ganic Substances Commonly Used in Pharmacy, Medi- cine, and the Arts 116 Inspection 116 Separation of Organic Compounds into Groups 117 Ultimate Qualitative Analysis of Organic Compounds.... 119 Summary of Non-nitrogenous Classes of Organic Bodies 126 Identification of Scaled Iron Compounds 129 CONTENTS. VII PAGE A Scheme for the Detection of Poisons 135 A Scheme for Uranalysis 137 Preparation of Reagents 149 Acids 149 Salts \ 149 Gases 150 Special Reagents 150 Index 153 QUALITATIVE CHEMICAL ANALYSIS. PART I. DEFINITIONS AND GENERAL CONSIDERATIONS. i. Matter.-The substance of which all bodies are con- stituted is called matter. Examples: Earth, wood, stone, air, vapor, water, etc. There are two kinds of matter, simple and compound. Matter exists in three states of aggregation; i.e., as solids, liquids, and gases. 2. Continuity of Matter.-Whenever a bar of any metal is heated it expands; when cooled it contracts. These changes are most reasonably accounted for by assuming that the metal is composed of minute particles which are not in absolute contact, and which may approach or recede from each other with the withdrawal or application of heat. This non-continuity is likewise proved when two liquids of different densities are mixed; for example, if 50 cubic centimeters of alcohol are mixed with 50 cubic centimeters of water, the product is not 100 cubic centimeters of mixture, but only 97 cubic centimeters, showing a loss in volume of 3 per cent. This reduction of volume clearly indicates that between the particles of one of the two liquids there must be open spaces which particles of the other liquid have filled up. There are many other considerations which lead us to 2 QUALITATIVE CHEMICAL ANALYSIS. believe that matter is not continuous as it appears to the senses and as generally believed, but is composed of exceed- ingly small particles which are not rigidly joined together, but are at relatively considerable, though exceedingly minute, distances apart; and that these particles are in a state of per- petual motion, which motion is increased by raising and de- creased by lowering the temperature of the mass. Matter is divided into three general divisions-masses, molecules, and atoms; and it is impenetrable and indestructible. 3. Mass, or body, is any distinct portion of matter appre- ciable by the senses. Molecules and Atoms.-A molecule (a little mass) is " the smallest particle of matter which can exist in a free state The small particles referred to in paragraph 2 are called molecules; and masses of matter large enough to be evident to the senses are aggregations of molecules. All compounds are made up of one or more distinct sub- stances into which they may be split. Since every compound can be split into at least two elements, it follows that its mole- cule must consist of one particle of each element. Hence there must be particles of matter smaller than the molecule itself. These smaller elementary particles, called atoms, are defined as " the smallest particle of matter that can enter a chemical combination''. Atoms are the constituents of molecules; they are indivisible and indestructible; under ordinary conditions they cannot exist free, but when forced from one combination immediately enter another. A collection of atoms forms a molecule, and a collection of molecules forms a mass. The molecules of compounds may consist of any number of atoms; molecules of elements usually of only two. 4. Elements and Compounds.-As stated in paragraph 1, there are two kinds of matter, the simple and the compound. Simple matter consists of only one elementary substance, as iron, lead, oxygen, carbon. Compound matter is com- DEFINITIONS AND GENERAL CONSIDERATIONS. 3 posed of two or more kinds of matter in combination, as iron oxid, which consists of iron and oxygen; and lead sulfate^ which consists of lead, sulfur, and oxygen. Simple matter cannot be reduced to anything simpler by any known means; it is therefore assumed to consist of but one kind of matter, and is called an element. About seventy-four different kinds of elementary matter, or so-called elements, are now known, and it is almost certain that others remain to be discovered. Out of these elementary substances the entire universe is constructed. The list of compounds, constantly increasing, is innumer- able. 5. Definition of Chemistry.-Chemistry is the science which considers the composition of substances and changes of com- position which they may undergo. Practically, the study of chemistry consists in subjecting materials to the action of certain substances called " re- agents ", or to the action of heat, light, or electricity, and noting the changes which may occur. These changes are called " reactions ", Chemistry deals with the atoms composing the molecules. It studies the properties of atoms, their association into molecules, their mutual attraction, the changes of their posi- tions on the application of various forces, the compounds they form when brought together with other atoms or molecules, etc. 6. Inorganic and Organic Chemistry.-By Inorganic Chem- istry we mean "the study of the compounds of mineral origin ". By Organic Chemistry is meant the study of the compounds formed in the tissues of plants or animals, and other "organ- ized " compounds. It is usually defined as " the chemistry of carbon compounds ". 7. Chemical and Physical Change.-Our knowledge of things is derived mostly by observing their specific properties, such as color, hardness, fluidity, transparency, odor, etc., and the changes which take place in them. 4 QUALITATIVE CHEMICAL ANALYSIS. These changes are comprised under two general headings, viz., physical changes and chemical changes. A physical change is one in which the composition and properties of a substance are not permanently altered. A chemical change is one in which both composition and properties are permanently altered and one or more new sub- stances produced. To illustrate the above-mentioned changes we will take common salt. It is a solid; when put into water it dissolves-a physical change occurs; now we apply heat, vaporize the water, and recover the original solid-unchanged common salt. If we now take the same salt and dissolve it in sulfuric acid, a chemical change takes place, and the products of this change, hydrochloric acid and sodium sulfate, are entirely unlike the common salt from which they were formed. The acid and the new salt formed are new compounds produced by a chemical change. 8. Compounds and Mechanical Mixtures.-These should be differentiated: In a mechanical mixture there is no true union of the elements; in a compound there is. As an example we will take iron and sulfur. Reduce the iron in a mortar to the finest possible powder; do likewise with the sulfur; now mix the powders intimately until the mixture presents a uniform appearance. Place a small quantity of it under a microscope and small particles of iron and sulfur lying side by side will be revealed. Now if another portion of the mixture is taken and heated to redness, a chemical change occurs, a true compound is formed, in which neither the iron nor the sulfur can be revealed under the microscope. Before heating, therefore, the powder was but a mechanical mixture, but after heating a true chemical compound, iron sulfid, is found to have been produced. 9. Molecular Attraction and Chemism.-Molecules attract one another. When the molecules are of the same kind they DEFINITIONS AND GENERAL CONSIDERATIONS. 5 form a homogeneous mass, and the force acting between them is called cohesion. When the molecules are not of the same kind the force of attraction is called adhesion. A piece of lead thrust into water comes out wet because of the water adhering to it. Try now to pull the lead apart to smaller pieces: you cannot, because cohesion keeps it together. Chemism is to molecules what cohesion is to masses. It is the force which attracts atoms to one another to form molecules. io. Atomic and Molecular Weights.-The atoms possess definite weights of their own. The atomic weight of any element is the number of times its atom is heavier than the atom of hydrogen, which, being the lightest substance known, is generally used as the standard of weight. Its atomic weight is taken as one ; that is, it weighs one microcrith. When, for example, oxygen is said to have the weight of 16, it is understood that its atom has a weight of 16 microcriths, or that it weighs 16 times as much as the hydrogen atom. Thus we say nitrogen weighs 14, carbon 12, sodium 23, calcium 40, etc. Molecular weight is the sum total of the atomic weights in a molecule of a substance. Thus the molecular formula of calcium carbonate is CaCO3; that is, it is composed of one atom of calcium having the weight of 40, one atom of carbon weighing 12, and three atoms of oxygen each weighing 16, or 48 for the three. Adding these atomic weights (40+12+48) together we get the sum of 100, which is the molecular weight of the calcium carbonate, or common chalk. ii. Valence, also called Quantivalence, or "Bonds".-By the "valence" of an element is meant "the combining power of one of its atoms as compared with that of hydrogen". As will be seen, hydrogen is also the "unit" of valence, as it is of weight. Atoms of certain elements, such as chlorin, are found to be equal in combining power to those of hydrogen; i.e., one atom of chlorin unites with one atom of hydrogen. Hydrogen being 6 QUALITATIVE CHEMICAL ANALYSIS. the unit has the valency of 1, or one bond; it is also called a "monad," or a "univalent" element. When it is said that oxygen has the valency of 2, or that oxygen is a dyad, it is meant that the combining value of its atoms is twice that of the hydrogen atom, and that in order to make these two combine two atoms of hydrogen must be employed to satisfy one atom of oxygen, thus: h>o=h2o. Nitrogen, having the valence of 3, is a triad, and requires 3 /H atoms of hydrogen to satisfy its atom, thus: N^-H = NH3. From the above we will see that the chemical value of any atom is equal to that of another atom which can replace it in a molecule. Thus atoms are divided into monads, dyads, triads, tetrads, pentads, hexads, heptads, etc., according as they can replace 1, 2, 3, 4, 5, 6, or 7 atoms of hydrogen or its equiv- alent in a molecule. An element, while it always has the same valence in the same compound, may have different valences in different com- pounds or combinations. In ammonia (NH3), for example, the valence of nitrogen is always 3, but in nitrogen pentoxid (N2O5) it is always 5; many other elements have this variable valence. A monad is equivalent to a monad. ' ' dyad 1 ' I i ' 2 monads or 1 dyad. ' ' triad ' ' C ( " 3 (( ' ' 1 monad and 1 dyad. " tetrad " C ( " 4 (< " 2 dyads or 1 monad) and 1 triad. ' ' pentad ' ' C c " 5 n 1 tetrad and 1 monad, 1 triad and 2 monads, " 2 dyads and 1 monad. The valence of an atom is often indicated by accents placed to the right of its symbol, thus: H', H'"; or by Latin numerals, as On, CIV, etc. DEFINITIONS AND GENERAL CONSIDERATIONS. 7 Notation, Classification, and Nomenclature of Elements and Inorganic Compounds. 12. Symbols.-For convenience in writing chemical reac- tions and for many other reasons, certain symbols are used which represent or stand for the names of elements. These symbols are the initials of their Latin names (H for hydrogen, 0 for oxygen, N for nitrogen, S for sulfur, etc.). When more than one element has a name beginning with the same letter, another characteristic letter is added. The first letter is always a capital, the second is small (Hg for hydrargyrum, Os for osmium, Ni for nickel, Sb for stibium, etc.). Each symbol stands for one atom of the element, unless a figure is attached to the upper or lower right-hand corner, which indicates a greater number of atoms: H' = l atom of hydrogen, H2 = 2 atoms of hydrogen. 13. Metals are Classified according to their chemical and physical relationship. The " Periodic System " groups the elements progressively in accordance with their atomic weights, thus exhibiting these relationships most perfectly. The arrangement used in this book groups the elements most advantageously for the practical work of the chemist. The following tables include the most important elements and acids. Students would do well to study carefully and commit to memory the grouping, symbols, and valences. In Table I we will find the Non-Metals classified. These may be solid, liquid, or gaseous at ordinary temperatures. They have no lustre, ductility, or malleability, are poor con- ductors of heat and electricity, and are electronegative in combinations. They are the Acid-jorming Elements. In Table II we find the Metals, or Base-jorming Elements. These are electropositive, solid (except mercury) at ordinary temperatures; generally heavy bodies, good conductors of heat and electricity, and possessing more or less lustre. 8 QUALITATIVE CHEMICAL ANALYSIS. In Table III the Acids are grouped according to their valence or basicity. An acid is defined as a " salt of hydrogen In reality " acids are the hydroxids of the non-metals ", and while not all the acids contain oxygen, every acid contains hydrogen. Acids containing oxygen are called oxacids, of which nitric acid (HNO3) is an example; those in which oxygen is wanting are classed as hydracids; thus hydrochloric acid (HC1) is a hydracid. An acid consists of two parts: Replaceable or basic hydrogen, and the acidulous radical The hydrogen may be replaced by a metal, and the acid radical may pass into another compound without splitting into its elements. The basicity or valence of an acid is determined by the number of replaceable hydrogen atoms it contains; thus, H(C1) is a monobasic acid, H2(SO4) is a dibasic acid, H3(PO4) is a tribasic acid, etc.; the acidu- lous radicals are in parenthesis. 14- TABLE I-NON-METALS. Grouping. Symbol. V alences. Atomic Weights. Hydrogen Group: Hydrogen H 1 1.0 Chlorin Group: Chlorin Cl 1, 3, 5 35 37 Bromin Br 1, 3, 5 79 76 lodin I 1, 3, 5 126.53 Fluorin F ' 1' 19 0 Suljur Group: Oxygen 0 2 15 96 Sulfur S 2, 4, 6 31 98 Selenium Se 2' 4, 6 79 Tellurium Te 2, 4; 6 128 Nitrogen Group: Boron B 3 10 9 Nitrogen N 3, 5 11 01 Arsenic As 3, 5 74 9 Antimony Sb 3, 5 119 6 Phosphorus P 3, 5 30.96 Carbon Group : Carbon c 2, 4 11 97 Silicon Si 2 28.3 DEFINITIONS AND GENERAL CONSIDERATIONS. 9 15. TABLE IL-THE METALS. Grouping. Symbol. Valence in -ou8 com- pounds. Valence in -ic com- pounds. Atomic. Weight Metals precipitated, by dilute HC1, whose chlorids, sulfids, hydroxids, and car- ' First Group: Silver Ag 1 107.66 I Lead Pb 2 206.4 bonates are insoluble in H2O. t Mercurosum. . . . Hg" 1 199.8 Metals precipitated by H2S in acid solution, whose f Second Group-Fir Arsenic st Divi As sion: 3 5 74.9 | Antimony Sb 3 5 119.6 (NH4)2S. [ Tin " Sn 2 4 118.8 Metals precipitated from ' Second Group-Sec Bismuth ond Di Bi vision: 3 5 208.9 acid solution by H2S,whose Copper Cu 1 2 62.18 sulfids are insoluble in (NH4)2S. Mercuricum Cadmium Hg Cd 2 2 199.8 111.5 f Third Group-First Iron Divisi Fe on : 2 3 55.88 Metals not precipitated 1 Cobalt Co 2 3 59.0 by H2S from acid solutions Nickel . . ..... Ni 2 3 58.6 but precipitated by (NH4)2S as sulfids. Manganese Zinc Mn Zn 2 3 2 54.8 65.1 Metals not precipitated by H2S from acid solutions [ Third Group-Seco -] Aluminum nd Div Al ision: 3 27.04 but precipitated by (NH4)2S as hydroxids. [ Chromium Cr 2 3 52.0 Metals not precipitated by sulfids, either from acid Fourth Group: Calcium - Strontium Ca Sr 2 2 40.0 87.3 or alkaline solution, but precipitated by carbonates Barium Ba 2 136.9 Magnesium Mg 2 24.3 ' Fifth Group: Lithium Li 1 7.0! Metals not precipitated by any general reagent. ■ Sodium Na 1 23 0 Potassium K 1 39.03 Ammonium nh4 1 18.0 10 QUALITATIVE CHEMICAL ANALYSIS. l6. TABLE III-THE ACIDS. Inorganic Hydracids. Name of Acid. Chemical Formula. Name of its Salt. Monobasic: Hydrochloric ... HC1 Chlorid < I Hydrobromic ... HBr Bromid (I Hydriodic ... HI lodid 11 Hydrofluoric ... HF Fluorid I ( Hydrocyanic ... HCN Cyanid Dibasic: Hydrosulfuric ... H2S Sulfid Tribasic: Hydroferricyanic ... H3FeCN. Ferricyanid Tetrabasic: Hydroferrocyanic ... H4FeCN6 Ferrocyanid Inorganic Oxacids. Monobasic: Chloric HC1O3 Chlorate ( I Bromic HBrO" Bromate < ( Iodic IIIO3 Iodate I ( Nitrous HNO, Nitrite (( Nitric hno3 Nitrate Dibasic: Sulfurous. . .. H2SO3 Sulfite i c Sulfuric H2SO4 Sulfate . c Thiosulfuric.. Thiosulfate (( Carbonic. . . . H2CO3 H2CrO4 Carbonate (( Chromic Chromate Tribasic: Phosphoric. . h3po4 Phosphate (I Arsenous. . .. H3AsO3 Arsenite (( Arsenic H3AsO4 Arsenate Organic Oxacids. Monobasic: Formic. . . HCHO2 Formate 1I Acetic hc2h3o2 Acetate 11 Lactic HC3H5O3 Lactate I ( Benzoic. . . . hc7h8o2 Benzoate 11 Salicylic. . .. hc7h5o3 Salicylate (( Valerianic. . hcsh 0, h2c4h6o8 Valerianate Dibasic: Malic Malate C I Oxalic. .... H2C2O4 Oxalate (I Succinic. . . . h2c4h4o4 Succinate ( c Tartaric. . . . h2c4h406 Tartrate Tribasic: Citric h3c6h507 Citrate i < Meconic.... h3c7ho7 Meconate 17. Importance of Symbols.-The symbols in Tables I and II represent not merely the name of the element, but also a definite weight of the latter. Thus the symbol 0 repre- sents not merely oxygen, but it stands for one atom of oxygen or 16 parts by weight; N represents one atom of nitrogen or 14 parts by weight; and C represents 12 parts by weight of carbon. DEFINITIONS AND GENERAL CONSIDERATIONS. 11 A Formula is an expression representing the composition of a molecule; it consists of two or more symbols written together, and therefore represents a definite weight, the molecular weight, which is the sum of the atomic weights of the constituent atoms. Thus H2O is the formula which represents water; its molec- ular weight is 18, i.e., 2 parts by weight of hydrogen and 16 parts by weight of oxygen. NaCl is the formula for sodium chlorid, and represents 58.4 parts by weight of sodium chlorid; 23 for the sodium and 35.4 for the chlorin. KOH is the formula for potassium hydroxid, and represents one atom of potassium, one of oxygen, and one of hydrogen, having the weights 39, 16; and 1 respectively. Hence KOH represents 56 parts by weight of potassium hydroxid. When we wish to represent more than one atom, we place a. small numeral at the right-hand lower corner of the symbol; thus O2 represents 2 atoms of oxygen, or 32 parts by weight; in the same way K3 = three atoms of potassium, B4 = four atoms of boron. When we wish to represent more than one molecule, we place a large numeral before the formula. Thus 2K0H repre- sents two molecules of KOH; the 2 multiplies each of the atoms in the molecule. 3H2SO4 represents three molecules of H2SO4; thus.it means, 6XH, 3XS, and 12X0. The three placed before the molecule multiplies the whole molecule; the smaller nu- merals in this case, 2 and 4, multiply only the atoms which immediately precede them; thus the H is multiplied by 2, and the 0 by 4. If a group of symbols is inclosed in a parenthesis and a small numeral placed after it, as in (NH4)2 and (SO4)3, the whole group is multiplied by the numeral. As symbols always represent atomic weights, so formulas represent molecular weights; thus the molecular weight of sodium sulphate, Na2SO4, is: Na2 (23X2)= 46, S = 32, 04 (16X4)= 64, which added together give 142. 12 QUALITATIVE CHEMICAL ANALYSIS. Equations are representations, by means of symbols, of chemical reactions. Example: Na2CO3 + 2HC1 = 2NaCl + H20 + C02. Sodium Hydrochloric Sodium Water. Carboa Carbonate. Acid. Chlorid. Dioxid. Na2(23X2) = 46 2H = 2 2Na = 46 2H= 2 C = 12 C =12 2C1 = 70.8 2Cl = 70.8 0 = 16 O2=32 O3(16X3)=48 106 72.8 116.8 18 44 This equation indicates that sodium carbonate treated with hydrochloric acid will yield sodium chlorid, water, and carbon dioxid. There are one molecule of Na2CO3 and two molecules of HC1 reacting, and producing two molecules of NaCI and one molecule each of H2O and CO2. Now since symbols represent definite weights, an equation can be easily reduced to figures. The atomic weights of the elements entering into the foregoing equation are Na = 23, C = 12, 0 = 16, H = l, and Cl = 35.4. Thus we have 106 parts of Na2CO3 reacting with 72.8 parts of HC1 and forming 116.8 parts of NaCI, 18 parts of H2O, and 44 parts of CO2. In an equation, the sum of the atoms on one side of the sign of equality [ = ] should equal that on the other. 18. Classification of Compounds.-Compounds are classified as bases, acids, and salts. Bases are the hydroxids of the metals. Slaked lime is the commonest example of this class. Some of the bases are soluble, others not; when soluble they have a caustic taste and turn red litmus blue. Acids are the salts of hydrogen; these are fully defined in paragraph 13 and classified in Table III. When soluble they have a sharp, sour taste and turn blue litmus red. DEFINITIONS AND GENERAL CONSIDERATIONS. 13 Salts are acids in which part or all the basic hydrogen has been replaced by a metal; thus, if the hydrogen of sulfuric acid is replaced by potassium, we have formed a salt, called potassium sulfate; if the hydrogen of acetic acid be replaced by potassium, we have a salt called potassium acetate. The salts are further classified into normal, acid, basic, and double salts. A normal salt is one in which all the basic hydrogen has been replaced by a metal, as in Na2COa, sodium carbonate. An acid salt is one in which some of the basic hydrogen still remains, as in NaHCOs, sodium acid carbonate. A basic salt is a substitution of a metal in part for the H of an acid, and in part for the half or the whole of the H of water; i.e., a basic salt is a compound partly of the nature of a salt and partly of the nature of a hydroxid or an oxid. Double salt is one in which the basic H of an acid is replaced by more than one metal. Example, KNaC4H406. The Names of Acids.-All the names of hydracids begin with hydro and end in ic, as hydrochloric, hydroiodic, hydrobromic, etc. In the oxacids, the quantity of oxygen present in acids of the Same element determines their names, thus: acids containing the least amount of oxygen begin with hypo and end in ous; those containing the next larger quantity of oxygen end in ous, omitting the hypo; those containing the next larger quan- tity of oxygen end in ic. If there is a fourth acid containing still more oxygen than the preceding one, its name begins with per and ends in ic. In this way we derive a table of the nomenclature of the acids. Following is a table of the chlorin oxacids: Formula. Name of Acid. HC1O Hypcchlorous HC1O2 Chlorous HC1O,< Chloric HC1O4 Perchloric 14 QUALITATIVE CHEMICAL ANALYSIS. The Names of Salts.-The names of salts also indicate their composition, both as regards their constituents and the quanti- ties of these present in them. The names of salts generally consist of two words, the first expressing the metal, the second expressing the acid radical; thus, sodium sulfate = Na2SO4; zinc chlorid=ZnCl2. The above is true only with the normal salts. In the case of acid or basic salts three and more words are required to express their name and composition, as in potassium acid carbonate, KHCO3, etc. As is seen in the above, the prefixes and suffixes employed in expressing the names of the acids and salts have a very important meaning, which the following further explains: The prefix sesqui is used to express a proportion of 1 to 1J, as in Fe2O3, iron sesquinxid. Prefix sub, when used, indicates a lower amount of an element than the name would otherwise represent; thus, Cu2O, copper suboxid. The prefix per or hyper or super (above) indicates the highest of a series of compounds, as contrasted with sub or hypo, indi- cating lowest. Examples: KC104, potassium perchlorate; Fe2Cl6, iron perchlorid. The prefix ortho (straight) is used to distinguish normal acids or salts. Example, H3PO4, or/Aophosphoric acid. The prefix pyro (by fire) is used to designate that the body has been produced by heat (fire). Thus 2H3PO4 or H6P2O8+heat becomes H4P2O7, pyrophosphoric acid, water (H2O) being driven out. C7H6O5, gallic acid, heated, becomes C6H6O3, pyrogallic acid, CO2 being driven out. The prefix meta is used to designate an altered condition as distinguished from the ortho and pyro (and para) forms. Thus H4P2O7+heat becomes 2HPO3, metaphosphoric acid, water being driven out. The prefixes ortho, meta, and para (near to) are used with organic compounds in which some of the constituent radicals are attached in certain relation to each other; these compounds DEFINITIONS AND GENERAL CONSIDERATIONS. 15 have the same chemical composition but differ in physical properties. The following examples illustrative of this show a difference in the place of attachment of the OH radicals; the chemical composition C6H4(OH)2 being the same in each. OH ^^OH is or^o-dihydroxybenzol, or pyrocatechin. OH ( ^ । weta-dihydroxy benzol, or resorcin. OH | is para-dihydroxybenzol, or hydroquinone. ^OH Para also indicates molecular aggregations of certain organic compounds, as C2H4O=aldehyd; and (C2H4O)3 or C6Hi2O3 = paraldehyd. The prefix hydro indicates binary compounds or acids, as fo/drochloric acid, HC1, hydromiimic, acid, H2S, etc. The prefixes an (without) and de (away from) are used to denote something which has been removed from a body in which it normally exists. Examples: anhydrous, without water or moisture; deodorized, deprived of odor. The nomenclature of salts corresponds to that of the acids; thus the name of a salt of an hypo . .. ous acid begins with hypo and ends in ite " " 11 " ous acid ends in ite " " " " zc 11 11 11 ate " " 11 a per . . . ic 11 begins with per and ends in ate. The following table of the chlorin oxacids with sodium illustrates this: 16 QUALITATIVE CHEMICAL ANALYSIS. Name of Acid. Name of the Salt. Hypochlorous acid forms Sodium Hypochlorite Chlorous " " Chlorite Chloric ' ' " Chlorate Perchloric " 11 Perchlorate For nomenclature of other salts see Table III. The name of a compound may also be varied in other ways to indicate its composition, as di-sodium phosphate, Na2HPO4, to indicate that only two atoms of basic hydrogen in phosphoric acid, H3PO4, have been replaced by the metal. By referring to Table II we note that many elements, as iron, bismuth and arsenic, form two or more classes of compounds corresponding to their varied valences. Names of these compounds in which the element has the lower valence end in ous', those in which it has the higher val- ence end in ic, as ferrous and feme salts, arsenous and arsenic salts, etc. The names of salts of all the hydracids end in id, as will be observed by referring to Table III; so also do the names of all other binary salts. The terms binary and ternary salts designate those composed of only two or of more elements; thus, KC1, KCN, etc., are binary compounds, and KC103, KSCN, etc., are ternary com- pounds. An oxid is a compound formed by the union of a metal or non-metal with oxygen. CaO, K2O, MgO, CO2, and N2O5. An anhydrid is a compound left after removing from an acid all its replaceable hydrogen and enough oxygen to form water. Examples. H2S04- H2O = SO3 = sulfuric anhydrid; 2H3PO4 - 3H2O = P2O5=phosphoric anhydrid; H2CO3- H2O = CO2 = carbonic anhydrid. PART II. IDENTIFICATION AND SEPARATION OF INORGANIC BASES AND ACIDS. INTRODUCTORY. 19. Qualitative Analysis has for its object, the resolving of more or less complex substances into simpler ones, without reference to the proportions or quantities of the latter present. By qualitative analysis usually we mean the examina- tion of salts, i.e., combinations of bases and acids, the prob- lem involved in such cases being the determination of the particular base and acid present in the given substance. Thus we examine a substance to determine not directly what ele- ments are present, but what metals and what acidulous radi- cals-the latter usually being groups of elements. For example, in the analysis of barium sulfate we do not search for Ba, S, and 0 separately, but for barium as the base and SO4 as the acidulous radical. In some such cases as ammonium carbonate, (NH4)2CO3, where neither the positive radical or base (NH4) nor the nega- tive or acidulous radical (CO3) can exist in the free or uncombined state, we detect the former by the evolution of ammonia-gas (NH3), and the latter by the expulsion of carbon dioxid (CO2), from the substance. The word analysis is the true antithesis of the word synthesis; analysis mean- ing splitting up or breaking up of a substance, while synthesis means the building up of a compound from its elements. 17 18 QUALITATIVE CHEMICAL ANALYSIS. Thus if we conduct an electric current into a solution of com- mon salt, we split the compound into its components Na and Cl. This process is truly analytical. If we now bring sodium and chlorin together under suitable conditions, sodium chlorid will be formed in a synthetical way. The word analysis, in chemistry, bears a wide meaning. It includes the manifold processes used by chemists in the identification of substances. Thus substances are often recog- nized by some characteristic appearance, like a particular crystalline form, when examined under a microscope, which operation is known as microscopical analysis. Often the pres- ence of certain elements in a substance is determined by exam- ining the light emitted when substances are strongly heated in a non-luminous flame before an optical apparatus known as a spectroscope, in which case the operation is known as spec- troscopic analysis. Again, the substance may be examined in a polariscope as to its effect on light (much employed in oil and sugar analysis). In this last case the operation is called polariscopic analysis. The majority of analytical operations depend on some chemical change or reaction. When this change occurs on strongly heating a substance and observ- ing its peculiar characteristics in the dry way, we call it a dry reaction. Again, when such a change occurs in the sub- stance in the liquid form, by the action upon it of another liquid known as a reagent, we call it a wet reaction. 20. Reagents, or substances used to bring about chemical changes, may be in either the solid or the liquid state. For convenience in operation they are usually employed as liquids.* Reagents are divided into three classes: General Reagents, or group reagents, which under certain suitable conditions react with and precipitate a whole group or class of substances of similar character. * Students should prepare their own reagents and not be kept in the dark as to their strength; it also gives them an idea of the delicacy of many of the reactions. INORGANIC BASES AND ACIDS. 19 Separatory Reagents, by means of which the substance under examination is separated from other members of the same group; and Confirmatory or Special Reagents, which are employed be- cause they produce a certain peculiar characteristic reaction with a particular substance under examination, thus identifying it without any further doubt. Reagents, says Prof. Newth, are "the tools with which the analyst works, and upon the intelligent and skilful use of them everything depends." To the above a word on the impurities in reagents may be added. The student should constantly bear in mind that the substances he is testing for may be present in the reagents as impurities. In all such cases test the reagent directly, and by all means make sure of its purity; it is imperative for two reasons: First: It precludes danger of serious errors, and Second: It forms a habit of making blank tests with re- agents and thus cultivating observation and logical reason-' ing powers. In the course of qualitative analysis wet reactions are thought the more important. When chemical reaction takes place between two or more substances in solution, and one of the products of the reac- tion is insoluble, it is thrown out of solution or precipitated, and is called a precipitate (abbr., ppt.). In these operations the phenomenon of precipitation is taken advantage of. In precipitation of a solution always add the reagent gradu- ally, and only until no further precipitate forms. This can be determined by permitting the precipitate to settle, or, in case of light and flocculent precipitates which settle very slowly, by filtering a little of the liquid and adding to the fil- trate a drop or two of the reagent. In this way we guard against adding too much of the reagent, 20 QUALITATIVE CHEMICAL ANALYSIS. which in many cases partly dissolves some of the precipitates -a very undesirable thing. In washing a precipitate, persist until the wash-water will no longer give test for any substance known to be present in the filtrate, for if the precipitate is not thoroughly washed, the metal will be found present in succeeding groups, which will cause confusion and perhaps error in the analysis. Guesswork will not do in these cases; you must be thorough, as on the complete precipitation of the substances and subse- quent thorough washing of the precipitates the success of the analysis depends. Separation of Groups. If it were possible to precipitate by a separate reagent each individual metal out of a solution containing several dif- ferent metallic salts, the analysis of such a solution would be a very simple matter. Chemical analysis is, however, not so simple, for each reagent will precipitate more than one metal, and therefore in a solution containing a large number of metals the separa- tion must be effected in groups. Thus assuming that we have a solution containing twenty- four of the more common metals which we wish to analyze, the procedure must be as follows: Hydrochloric acid is added to the solution in slight excess. This causes the precipitation of lead, silver, and mercury (if this is in the form of a mercurous salt), as chlorid. (The Metals of Group I.) The hydrochloric acid should be added in sufficient quantity to pre- cipitate all the lead, silver, and mercurous mercury (mercurosum) that may be present in the solution. To insure this, the precipitate is allowed to settle, and the clear liquid above it treated with a few drops more of hydrochloric acid. If this fails to produce a precipitate, the acid has been added in sufficient quantity. If, however, a precipitate is produced, more hydrochloric acid must be added. A large excess, however, is to be avoided. INORGANIC BASES AND ACIDS. 21 N.B. Bismuth and antimony are precipitated by diluted hydrochloric acid, in the form of oxychlorids. Such a precipitate must not be mistaken for that of the metals of Group I. Having precipitated the metals of Group I as above described, allow the precipitate to settle, and pass the supernatant liquid through a filter. This solution, which contains the remaining twenty-one metals, is treated with excess, of the Group II re- agent, namely, hydrogen sulfid (H2S). This causes the separa- tion of seven more metals, namely, mercury in mercuric salts (mercuricum), copper, bismuth, cadmium, arsenic, antimony, and tin, in the form of sulfids. (The metals of Group II.) These metals take up the sulfur from the hydrogen sulfid and form in- soluble sulfids. In color the sulfids of mercury, copper, and bismuth so precipitated are black, cadmium and arsenic yellow, antimony orange, and tin brown or yellow. The hydrogen sulfid is best used in the form of the pure gas, which should be allowed to bubble through the solution until the latter is thoroughly saturated. A saturated aqueous solution of the gas is sometimes used instead of the gas itself. Having precipitated the metals of Group II, separate the precipitate by filtration. The filtrate now contains only four- teen metals. To this filtrate is added ammonium chlorid, about | its volume, and ammonium hydroxid in sufficient quantity to render the solution alkaline, then a slight excess of ammonium sulfid. Another separation of seven metals will take place, namely, iron, zinc, aluminum, manganese, chromium, cobalt, and nickel, as sulfids except aluminum and chromium, which sep- arate as hydroxids. (The Metals of Group III.) The sulfur of the ammonium sulfid unites with the metals, iron, zinc, manganese cobalt, and nickel forming sulfids of these metals, but chrom- ium and aluminum are precipitated as hydroxids. In color the precipitates produced with iron, cobalt, and nickel are black, with manganese flesh color, with zinc and aluminum white, and with chromium pale greenish. Having added sufficient of the ammonium sulfid (the Group HI reagent) to completely precipitate the metals, the 22 QUALITATIVE CHEMICAL ANALYSIS. mixture is again filtered in order to separate the precipi- tate. If now to the filtrate, in which only seven metals are left, an excess of ammonium carbonate solution be added, the metals barium, calcium, and strontium are precipitated in the form of carbonates {Group IV), leaving in solution magnesium, potassium, sodium, ammonium, and lithium. (Group V.) From this solution the magnesium may be precipitated by adding sodium phosphate. Since much ammonium has been added in the course of the analysis, a special test must be made for it in the original solution. Each group of metals separated as above described is further separated into its component metals according to the charts, and each metal identified by characteristic tests. These tests in most instances cannot be applied satisfac- torily unless upon solutions of single metals. THE SYSTEMATIC ANALYSIS OF A CHEMICAL SUB- STANCE, SIMPLE OR COMPOUND. 21. First, if a solid: a. Examine its general and physical characteristics, such as color, odor, reaction, structure (whether crystalline or amorphous), gravity, hardness, etc. b. Examine its solubility in water. c. Test its aqueous solution with litmus paper, both blue and red. If neither paper is affected, it is neutral. d. Heat a few centigrams of it with some NaOH or KOH in a test-tube, and note the odor. If NH3 odor is noticed, it indicates the presence of an ammonium compound; if it turns black, a mer- curosum salt (example, calomel) is present. Apply special tests for ammonium. INORGANIC BASES AND ACIDS. 23 Second, if a solid: (a) Heat about 20 centigrams of the solid in a dry test- tube held horizontally over a Bunsen-burner flame, and carefully note the effect. By holding the mouth of the tube lower than the bottom all the moisture is permitted to run out, thus preventing its running back upon the over- heated portion of tube and breaking it. (6) If the substance will blacken or char (due to the sepa- ration of carbon), it indicates the presence of an organic substance, like tartartes, citrates, sugar, alkaloid, gum, etc. It may here be added that a few organic substances, like the formates, oxalates, ferro- and ferricyanids, and cyanids, do not char. (c) To remove the'carbon thus obtained, let the test- tube cool off, add some strong H2SO4, and heat again. This treatment removes all the carbon from the tube. Third, if a liquid: (a) Test its reaction with both red and blue litmus, and observe whether it is alkaline (red paper turns blue with alkalies), acid (blue paper turns red with acids), or neutral (it does not affect the color of either paper.) (&) Evaporate a portion of the liquid to dryness in a capsule, carefully noting the odor of the fumes (as NH3, HCN, Cl, CIO, N02, etc., are thus detected). (c) Heat the residue strongly. Charred or blackened residue indicates presence of organic matter. (d) If the residue obtained above is not charred upon heating, it probably contains no organic matter, and is to be analyzed systematically and identified by chart 27 and the steps following. 24 QUALITATIVE CHEMICAL ANALYSIS. Fourth, a solid or residue of a liquid can very frequently be identified by applying such preliminary examination as: (a) Heat test for solids, par. 22; for acids, par. 76 (6) Flame test, described in 11 63 (c) Sulfuric-acid test, 11 " " 23 (d) Borax-bead test, " " 11 71 (e) Charcoal test, 11 11 " 24 (f) Sodium-carbonate test, ' ' 11 11 25 (g) Hydrochloric-acid test, " ' ' " 26 Having applied all the above tests and not having identified the substance, examine it according to the table 27 for the identi- fication of a simple substance. By carefully applying the above-mentioned classes of tests nearly all the common metals and their salts may be readily detected. In cases where the preliminary examination shows a number of metals present, separate them by carefully following the tables for the separation of the common metals. Heat Test. 22. Heat a little of the substance as described in Second, above, and observe closely: Observation. Indication. Substance blackens (carbonizes). Presence of organic substance or of a metal forming a black oxid. Moisture deposited. Hydrate, or salt containing water of crystallization. White sublimate formed in upper end NH4, Hg. (If accompanied by odor of of test-tube. garlic, it is As.) White sublimate + odor of NH3. Ammonium benzoate. Black sublimate + violet vapors. lodin or unstable iodid. Reddish fumes. Nitrites or nitrates. Reddish-brown fumes, and drops S or persulfids. which harden on cooling to yellow Oxid, masses. O2 gas. Inflames a glowing taper Chlorate, Perman- ganate 25 INORGANIC BASES AND ACIDS. Observation. Indication. SO, gas (odor of burning sulfur). Sulfate, sulfite, or sulfid. NH3 gas (its odor). Ammonium salts, a cyanid, or nitro- genzed organic substance. CO gas (burning with a blue flame). An oxalate. CO2 gas (causing turbidity in a drop Carbonates, oxalates, and all carbon- of Ba(OH)2, held on a rod above mouth of tube). aceous matter. Cl2 gas evolved. Hypochlorates. Acetone evolved (bums). Acetates. Odor of valerianic acid. Valerianates of zinc or soda. " " phenol. Carbolates, sulfocarbolates, or salicyl- ates. " " phosphorus (burning). Hypophosphite. " " burnt sugar. Saccharose, lactose, glucose, tartrates. " " burnt hair. Alkaloid. Sulfuric-acid Test. 23. Heat a portion (1 gm.) of the substance with a few drops of strong sulfuric acid, and observe: Observation. Indication. Violent effervescence (no odor). Effervescence + acid fumes; fumes white with ammonia. Green or yellowish-green solution. Red solution (at once). Bluish solution forms. Brown solution forms. Chars to burnt sugar. Yellowish gas evolved (with crackling explosions). Violet fumes evolve. Chars at first, with evolution of pun- gent acid fumes. Reddish fumes evolved. Odor of burning sulfur. Vapors evolved which, kindled, burn Carbonates or acid carbonates. Chlorid or nitrate. Chromium compound. Salicin. Ferrocyanid. Tannin. Saccharose or glucose. Chlorate. lodid. Citrate. Nitrite, nitrate, or bromid. Sulfite or thiosulfate. Oxalates or ferri- and ferrocyanids. with a blue flame (CO). Odor of HCN or vinegar. Cyanid or acetate. 26 QUALITATIVE CHEMICAL ANALYSIS. The Charcoal Test. 24. Heat a few centigrams of the substance on charcoal in the reducing (inner flame) with a blowpipe to red heat, and observe: Observation. Indication. It decrepitates. Chlorid or iodid. It fuses readily and is absorbed by Alkaline salts. the charcoal. It deflagrates, igniting the charcoal. A chlorate or nitrate. A white mass, highly Idminous, Alkaline earths of A12O3, SiO2, ZnO, while heated, remains. Ba, Sr, Ca, Mg, or Sn. Moisten the residue obtained above Blue=Al2O3 or phosphates and sili- with solution CO(NO3)2, and heat strongly. cates. If color is pale pink = MgO. " " " green = ZnO, Sb. A colored residue is left on charcoal. An incrustation is formed on char- Cu, Co, Fe, Ni, Mn, Cr. NH4, Hg, Sb. coal. An incrustation with odor of garlic. White = As. An incrustation yellow while hot. Greenish-white = Zn. An incrustation. Reddish brown=Cd. SODIUM-CARBONATE TEST. 25. Mix about one gram of the substance with about 10 grams of sodium carbonate, and heat on charcoal in the reducing flame by means of a blowpipe, and observe: Observation. Indication. Metallic bead, malleable, with yellow Lead. incrustation. Malleable metallic bead with no in- Silver. crustation. Malleable bead with white incrustation Tin Brittle bead with yellow incrustation. Bismuth. Brittle bead, no incrustation. Copper. Brittle bead with rvhite incrustation. Antimony. Grayish-black powder. Iron, cobalt, nickel, or manganese. Brown incrustation. Cadmium. INORGANIC BASES AND ACIDS. 27 The Hydrochloric-acid Test. 26. (1) Heat some of the substance in a test-tube with a little dilute HCl, and observe: A gas is evolved: Indication C02 (apply lime-water test). Carbonates. HJS, odor. Sulfids. SO2, odor of burning sulfur. Sulfites and thiosulfates. Cl, odor; apply bleaching test. IIC1O3, or oxidizes like chromates or chlorates. HCN (smell of bitter almonds). Cyanids. (2) Boil some of the substance in a test-tube with con- centrated HCl. If not all dissolved, pour off the solution and divide it into five equal parts, to which apply the following tests: To part 1 add KI, red ppt. soluble in excess. " " 2 add KI, yellow ppt. insoluble in excess. Mercuricum. Lead. il " 3 add NH4OH; blue color develops. Copper. " " 4 add K4FeCy6; blue precipitate. Iron. Part 5. Evaporate to about one-fourth its original volume, pour a few drops of it into some cold water. White ppt. indicates either Bismuth or antimony 28 QUALITATIVE CHEMICAL ANALYSIS. 27. TABLE FOR THE IDENTIFICATION Group. Reagent. Result. Indication. Form. I To a portion of the orig- inal solution add HCl, drop by drop, until no further precipitate falls. A curdy white precipi- tate, insoluble in ex- cess of HCl. Pb Ag Hg' OUS 11. If no ppt. with HCl, or if the ppt. is soluble in excess of the reagent, Black precipitate Cu pass II2S through the acidified solution. ll 11 11 n Dark-brown ' ' Yellow I I 11 Orange Brown ' ' Yellow " Hg" Pb Bi Cd As Sb Sn Sn ic OUS ic III. If no precipitate with H2S, add to fresh por- tion of original so- Black precipitate Fe OUS • lution first NHjCl, then NH4()H, and NH4SH. Warm and filter. (I Cl ll ll Cl ll White " I1 11 Fe Co Ni Zn* Al* ic * If the ppt. in Group III is white in color and does not answer tests for Al or Zn, it may contain insoluble phosphates, metals, or oxalates, or all of these. Confirm by dissolving some of the original substance in cone. HNO3 and pouring this into sol of ammonium molybdate. INORGANIC BASES AND ACIDS. 29 OF THE METALS. Confirmatory Tests, which should be applied to original solution. Proof. Ppt. soluble in boiling water. Add KI yellow precipitate Test also by 2° and 3°, paragraph 30. Ppt. insoluble in boiling H2O. Add NH4OH, the ppt. dissolves Pb Ag Test also by 1°, 2°, and 3°, paragraph 31. Ppt. insoluble in boiling H2O. Add NH4OH, the white ppt turns black Hg' Test also by 2° and 3°, paragraph 32. Ppt. soluble, on heating, in excess of HC1 Sb or Bi Ppt. soluble in KCy. Add NH40H=a light-blue ppt. soluble in excess Cu Test also by 3° and 49, paragraph 38. Ppt. insoluble in (NH4)2S. Add KI = a red ppt. soluble in excess Hg" Test also by 3°, paragragh 36. Ppt. insoluble in (NH4)2S Add K2CrO4 = a yellow ppt Pb Test also by 3° and 1°, paragraph 30. Ppt. insoluble in (NH4),S. Add KI=a greenish-brown ppt.. . . Bi Test also by 3°, paragraph 37. Ppt. insoluble in (NH4)2S, soluble in HNO3. Add NH(OH=a white ppt soluble in excess Cd Test also by 3° and 2°, paragraph 41. Ppt soluble in (NH4)2S, reprecipitated by HC1 Test also by 3°, 4°, and 5°, paragraph 40. Ppt soluble in (NH4)2S, seprecipitated by HC1 Sb Test also by 3°, paragraph 42. Ppt. soluble in (NI14),S, reprecipitated yellow by HC1. Add NaOH-white ppt.; boil, ppt. insoluble Sn" Test also by 3° and 2°, paragraph 44. Ppt. soluble in (NH4),S, reprecipitated by HC1. Add NaOH= white ppt • boil, ppt dissolves SnIV Test also by 2°, paragraph 43. Ppt. soluble in HC1. Add K4FeCy6= white ppt., rapidly turn- ing blue Fe" Test also by 2° and 3°, paragraph 49. Ppt. soluble in HC1. Add K4FeCy6= heavy-blue ppt. insoluble in acids Fe"' Test also by 3°, 4°, and 2°, paragraph 48. Ppt. insoluble in dil. HC1. Add NH4OH=a blue ppt. soluble in excess to a brown solution Co Test also by 2°, paragraph 50. Ppt. almost insoluble in dil. HC1. Add K3FeCy8=a yellow ppt. Ni Test also by 3° and 2°, paragraph 51. Ppt. soluble in HC1. Add K4FeCy8= white ppt Zn Test also by 2°, paragraph 52. Ppt. soluble in HC1. Add KOH = white ppt. soluble in excess, Al Test also by 3°, paragraph 53. Yellow precipitate or coloration on boiling indicates insoluble phosphate; in which case treat as described later on. 30 QUALITATIVE CHEMICAL ANALYSIS. Group. Reagent. ' Result. Indication. Form. III. (con'd) Flesh-colored precipitate Mn ». Green precipitate Cr IV. If reagents of Group III give no precipitate, add (NH4)2CO3. Warm and filter. White precipitate It It Ba Sr ll 11 Ga V. If reagent of Group IV gives no precipitate, add Na2HPO4. White precipitate Mg TABLE FOR THE IDENTIFICATION If reagent of Group IV gives no ppt.. 28. CHART FOR THE SEPARATION OF THE METALS. Group I. Group Reagent: Dilute hydrochloric acid. To a portion of the original cold solution add some dilute HC1. A white curdy precipitate indicates: 1.* Pb, Ag, Hg' (ous), (Sb, Bi). 3. Insoluble in excess. Pb, Ag, Hg. . . Wash with cold H2O, then pour boiling H2O over precipitate. 2. Soluble in excess. Sb, Bi. These are confirmed in the next group. i 5. Insoluble. Ag, Hg'. Pour over precipitate some warm NH4OH. 4. Soluble. Pb. Confirm by adding H2SO4 white ppt. = Pb. KI yellow ' ' = Pb. K2CrO4orange-yel. " =Pb. 7. Insoluble. Hg. Pour over this black ppt. on filter a few drops of aqua regia, dilute with H2O, add some SnCl2: grayish or blackish ppt. = Hg. 6. Soluble. Ag. Confirm by adding HNO3 in excess: white ppt. = Ag. *The numbers refer to numbers of the Nofes. INORGANIC BASES AND ACIDS 31 OF THE METALS-Continued. Confirmatory Tests, which should be applied to original solution. Proof. Ppt. soluble in dil. HC1. Add KOH = white ppt.; shake; turns Mn Test also by 2°, 3°, and 4°, paragraph 54. Ppt. soluble in dil. HC1. Add KOH = green ppt. soluble in ex- ppqq rpnrecioitated on boiling: Cr Test also by 2° and 3°, paragraph 55. Ppt soluble in HC1 Add K2CrO4 - yellow precipitate Ba Test also by 3° and 4°, paragraph 59. Ppt. soluble in HNO3. Add K2CrO4=no ppt. Add sol OaSO shake- white ppt Sr Test also by 3°, paragraph 60. Ppt. soluble in acids. Add K2CrO4=no ppt. Add sol. CaSO4 shake=no ppt. Add (NHJ2CrO4=white ppt Test also by 3°, paragraph 61. Ca Add tNTTd i CO and boil - white DDt Mg test for K, Na, and NH4, as per paragraph 62. 2g. Notes on Group I. (1) On the addition of HC1 the following chlorids are formed: lead chlorid (PbCl2), silver chlorid (AgCl), and mercurous chlorid (HgCl). These being insoluble are precipitated together with the oxychlorids of antimony (SbOCl) and bismuth (BiOCI). The first three are insoluble in weak acids; the remaining two are soluble in excess of weak acids and water, therefore remain in the filtrate. Lead chlorid is slightly soluble in water, and when present in mere traces only, it passes into Group II, where it precipitates as sulficl. It is advisable to use dilute HC1 for two reasons: (a) Strong HC1 precipitates various other salts from strong solutions. (6) AgCl and HgCl are to some extent soluble in strong HC1; traces of these might therefore be overlooked. (2) The BiOCl and SbOCl are soluble in HC1, and hence pass over into Group II. 32 QUALITATIVE CHEMICAL ANALYSIS. (3) When boiling H20 is poured over the precipitate, the lead chlorid being soluble passes through the filter and deposits on cooling. The presence of lead in the filtrate may be proven by divid- ing it into three portions, and tests applied to each portion. See par. 30. (5) When solution of NH40H is poured over the precipi- tate left on filter, the AgCl dissolves, forming argentic amin, AgCl(NH3)2. The insoluble ppt. left on the filter is the black mercurous amin, NH2Hg2Cl, which is rather unstable and yields some metallic mercury by decomposition. (6) The addition of the HNO3 in the confirmatory test neutralizes the ammonia, and the AgCl is thrown down as a white curdy precipitate. % (7) The Hg" may also be proved by mixing some of the black precipitate with dry Na2CO3 and heating in a tube, when metallic globules or a mirror of mercury will be formed. When aqua regia is poured over the precipitate it forms mercuric chlorid (HgCl2), which is reduced by stannous chlorid (SnCl2) to grayish-white mercurous chlorid (Hg2Cl2) or black- ish-gray metallic mercury (Hg). SPECIAL TESTS FOR METALS OF GROUP I. (Chlorid Group.) Each of these tests should be applied to a fresh portion of the original solution. 30. Lead. Precipitated by HCl=a white crystalline precipitate of PbCl2 soluble in hot water: Pb(NO3)2 +2HC1 = PbCl2 +2HNO3. Plumbic Chlorid. INORGANIC BASES AND ACIDS. 33 1°. The lodid Test: KI gives a crystalline yellow ppt., Pbl2, soluble in hot water: Pb(NO3)2 +2KI = PbI2 +2KNO3. Lead lodid. 2°. The Chromate Test: K2CrO4 gives a bright-yellow ppt., PbCrO4, soluble in NaOH: Pb(NO3)2 +K2CrO4 = PbCrO4 +2KNO3. Lead Chromate. 3°. The Sulfuric Acid Test: H2SO4 gives a white ppt., PbSO4, soluble in NaOH: Pb(NO3)2 +H2SO4 = PbSO4 +2HNO3. Lead Sulfate. 31. • Silver. Precipitated by HCl = a white ppt. AgCl, soluble in NH4OH; reprecipitated by HNO3: AgNO3 +HC1=AgCl +HNO3. Silver Chlorid 1° Ammonia Test-NH4OH=a brownish-gray ppt., Ag2O, soluble in excess: 2AgNO3 +2NH4OH=Ag2O +2NH4NO3 +H2O. Silver Oxid. 34 QUALITATIVE CHEMICAL ANALYSIS. 2° Chromate Test.-K2CrO4 = a brick-red ppt., Ag2CrO4, soluble in NH4OH: 2AgNO3 +K2CrO4 = Ag2CrO4 +2KNO3. Silver Chromate.] 3° lodid Test.-KI = a pale-yellow ppt., Agl, insoluble in NH4OH: AgNO3 +KI=Agl +KNO3. Silver lodid. 32. Mercurous Salts. Precipitated by HCl = a white ppt., HgoCh, blackened by NH4OH: Hg2(NO3)2 +2HCl = Hg2Cl2 +2HNO3. Mercurous Chlorid. 1° lodid Test.-KI = a greenish-yellow ppt. of IIg2I2: Hg2(NO3)2 +2KI = Hg2I2 +2KNO3 Mercurous lodid. i 2° Ammonia Test.-NH40H=a black ppt. insoluble in excess.* Hg2(NO3)2+2NH4OH=NH2Hg2NO3 +NH4NO3 +2H2O. Mercurous Ammonium Nitrate. INORGANIC BASES AND ACIDS. 35 33. CHART FOR SEPARATION OF GROUP II. Pass H2S gas into the hot filtrate of Group I until it smells strongly of the gas after shaking. Heat to boiling, pass some more H2S into the solution, allow the precipitate to subside, filter, wash the precipitate with boiling-hot water until free from acid. Test a small portion of the filtrate, diluted with water, by passing more H,S through it, to see if the precipitation is com- plete. The precipitate may contain Cu, Pb, Hg, Bi, Cd, As, Sb, Sn. Wash with boiling-hot water, add a few drops of NH40H and excess of (NH4)2S. 8. Soluble. As, Sb, Sn. Add dil. HC1, filter and wash and dis- solve in strong HC1, boil gently, filter. I 11. Insoluble. Cu, Pb, Hg, Bi, Cd. Wash, pour dil. boiling HNO3 over the filter. 12. Insoluble. Hg. Dissolve in aqua regia by aid of heat. Evapo- rate to dryness, dilute with H2O, and add KI: red ppt. = Hg. 13. Soluble. Cu, Pb, Bi, Cd. Add dil. H2SO4, boil well, filter. 9. Insoluble. As and S. Apply Marsh's test. 10. Soluble. Sn and Sb. Boil with copper turnings and di- vide into two portions. 14, Insoluble. Pb. Dissolve the ppt.in NH4C2H3O2, add KI: yel. ppt. = Pb. AddK2C2O4: orange ppt. = Pb. 15. Soluble. Cu, Bi, Cd. Dilute with H2O, add excess of NH4OH and filter. 1 Add HgCl, white Confirm pres- or grayish ppt. ence of Sb by = Sn. Marsh's test. 16. Insoluble. Bi. Wash, dissolve in small quantity of warm dil. HC1, evaporate to a low bulk, and pour into a large volume of water: white ppt. = Bi. 17. Soluble. Cu, Cd. A blue solution indicates Cu. Add a little HNO3. Divide into two por- tions. AddNH4OH: blue=Cu. Add NH4OH, acid- ulate with HC1, pass H2S: yel. ppt. = Cd. 36 QUALITATIVE CHEMICAL ANALYSIS. 34- Observations on Group II. The separation of the members of this group requires very- careful manipulation to insure success. The precipitate may contain any or all of the following metals possessing characteristic colors, thus: Black or brown- ish black: CuS, PbS, HgS, Bi2S3, SnS. Yellow: CdS, As2S3, As2S5, SnS2. Orange: Sb2S3, Sb2S5. When H2S is first passed into solutions containing lead and mercuric mercury they give colored precipitates due to formation of double salts, thus: HgCl2Hg. At first it is white, then it turns red, brown, and finally black under the continuous action of H2S, owing to the formation of HgS. Lead salts under like condi- tions give red precipitates gradually changing to brown, then to black, owing the conversion to PbS. In addition to the above-mentioned sulfids of this group a white precipitate of sulfur is formed, especially if the original solution is very acid or when it contains a ferric salt, chromic or nitric acid, or a chlorate. These substances being strong oxidizing agents will be reduced by the H2S, precipitating sulfur, which is easily distinguished from CdS and As2S3 by its lighter color and density. Ferric salts will be reduced to ferrous salts: Fe2Cl6 +H2S = 2FeCl2 +2HC1+S. Chromic acid will be reduced to chromic chlorid: 2H2CrO4 +3H2S +6HCl = Cr2Cl6 +S3 +8H2O Nitric acid will be reduced to nitric oxid: 2HNO3 +3H2S=2NO +S3 +4H2O. As said above, it is almost useless to pass H2S into very acid solutions, especially those containing HNO3 or aqua regia. If these acids have been used in dissolving the original, the solution so formed should be first evaporated to dryness INORGANIC BASES AND ACIDS. 37 the residue dissolved in a little water with the aid of a few drops of HC1, before passing H2S into it. It is, however, essential that the solution be slightly acid; this is necessary to prevent the precipitation of Zn, Co, and Ni. Complete precipitation of the second group often seems tedious, but it should under no circumstances be scamped, if accurate and definite results are to be obtained. To attain this end it is necessary, first, to pass a sufficient quantity of H2S; second, to test a portion of the solution by filtration, dilution, and repeated precipitation until the satura- tion be complete. 1 The metals precipitate much more quickly from a hot than a cold solution, especially arsenicum; its yellow precipitate forms very slowly, thus: 2H3AsO4+5H2S = As2S5+8H2O; and to facilitate its precipitation the solution should be well heated from time to time. Besides the above reason, the sulfids thus precipitated from hot, weakly acid solutions and allowed to stand may be filtered much more easily, for they' exhibit to a marked degree the property of becoming "colloidal" and consequently passing through the filter-paper upon washing. If water saturated with H2S or very dilute aeetic acid be used for washing the precipitate, this tendency is checked. 35. Notes on Group II. 8. The object of adding a little NH4OH before the addi- tion of (NH4)2S is to neutralize the acid present, thus preventing the precipitation of sulfur. The precipitate should be digested, not boiled: boiling precipitates some As, Sb, Sn. These sulfids unite with the (NH4)2S, with the formation of salts of the sulfo-acids, thus: As2S3+3(NH4)2Sz=2(NH4)3AsS3; Sb2S3+3(NH4)2Sz=2(NH4)3SbS3; SnS + (NH4)2Sa;= (NH4)2SnS2. 38 QUALITATIVE CHEMICAL ANALYSIS. The (NH4)2S solution should be warmed with diluted HC1 (the strong acid dissolves Sb2S3). This reprecipitates all the sulfids which must be filtered off and washed from the soluble ammonium compounds. This reprecipitation is due to the instability of the free acids (formed by the HC1) corresponding to the sulfo- acid ammonium compounds above mentioned. On adding strong HC1 and boiling, Sb and Sn dissolve as chlorids, while the yellow arsenic sulfid remains undissolved. The boiling is necessary to drive off the H2S. 9. The black spot formed in Marsh's test is soluble in solu- tions of chlorinated soda or calcium. If part of the solution is treated with CS2, and this solution allowed to evaporate spontaneously, free S is separated. 10. The acid solution on being boiled with metallic copper (preferably turnings) reduces the stannic chlorid to stannous according to the reaction SnCl4 + Cu = SnCl2 + CuCl2. The SnCl2 reduces mercuric chlorid (HgCl2) to the mercurous chlorid (Hg2Cl2) or gray metallic Hg, according to the quantity of SnCl2 present. 11. The precipitate should be well washed to insure absence of the metals of Group III, as the (NH4)2S will precipitate the metals of the aluminum and iron groups. 12. Mercuric sulfid (HgS) is insoluble in boiling dilute HN03, but, owing to the presence of other sulfids, the treat- ment with HN03 will cause evolution of H2S and formation of nitrates and free sulfur, thus: 3H2S +2HNO3 = S3 +2NO +4H2O. The free sulfur thus formed occludes a portion of the sulfids other than HgS, and protects them from action of the HN03. Therefore the black residue thus formed which is insoluble in HN03 should always be further tested before rejecting it. HgS dissolved in aqua regia forms HgCl2; this should be evaporated to dryness to get rid of the chlorin, which would liberate free iodin on the addition of KI. INORGANIC BASES AND ACIDS. 39 The KI should be added drop by drop, as the red mercuric iodid (Hgl2) thus formed is soluble in excess of the reagent. Hg may further be identified by adding a few drops of solution stannous chlorid (SnCl2), when a grayish-white precipitate will form. Or, the precipitated HgS may be fused with potassium cyanid (KCy) and sodium carbonate (Na2CO3) in a dry tube, when Hg will sublime a little above the fused mass. 13. The sulfids of Cu, Pb, Bi, Cd, dissolve in the nitric acid, forming corresponding nitrates. Evaporate this nitrate solu- tion to about one-fourth the original bulk and add sufficient dilute H2SO4 to displace the nitric acid and form corresponding sulfates. Continue evaporation until white H2SO4 fumes appear. This is a sign that all the HNO3 is dissipated, which is important for the reason that lead nitrate might remain in solution and interfere in the detection of cadmium. Cool the solution of sulfates, and dilute with water. The sulfates of bismuth, copper, and cadmium go in solution and may be readily filtered off from the insoluble PbSO4. 14. Lead sulfate dissolves readily in ammonium acetate, forming a double salt. Divide this solution into two portions; to one add KI; lead iodid will form: PbSO4 +2KI = PbI2 +K2SO4. To the other portion add K2CrO4; lead chromate will form according to the reaction PbSO4 + K2CrO4 = PbCrO4+K2SO4. Lead iodid forms a yellow, and the chromate an orange-colored, precipitate. Either of the reagents may be applied directly to the PbSO4 on the filter. 15. The filtrate must be slightly diluted with water before addition of NH4OH. The Cu and Cd dissolve in the ammonium hyclroxid to form soluble ammonium compounds, while the Bi is precipitated as hydroxid, Bi(OH)3. 16. Filter off the Bi(OH)3 and dissolve it on the filter by pouring warm dilute HC1 over the precipitate, returning the filtrate until all the precipitate has passed into solution. The solution contains BiCl3, and on evaporating it to a small bulk to free it from excess of the HC1 and pouring it into a large 40 QUALITATIVE CHEMICAL ANALYSIS. volume of water, a white, cloudy precipitate of bismuth oxy_ chlorid (BiOCl) is produced. The evaporation to a small bulk above directed is for the purpose of increasing the delicacy of the test, as the less HC1 used for dissolving the Bi(OH)3 the more positive does this reaction become. 17. If the solution be of a blue color, it indicates the pres- ence of copper, the color being due to the formation of a new compound, ammonio-sulfate of copper. Add to this solution a few drops of HNO3, and divide into two portions, a and b. To portion a add NH4OH; a blue color = copper. Toportion b add NH4OH, acidulate with HC1, and pass H2S through the solu- tion; a yellow precipitate indicates cadmium sulfid, CdS. SPECIAL TESTS FOR METALS OF GROUP II. (Acid Sulfid Group.) Each test to be made upon a fresh portion of the original solution. 36. Mercuricum. Precipitated from acid solution by H2S = a reddish-black ppt. of HgS, insoluble in HNO3: HgCl2+H2S = HgS+2HCl. Mercuric Sulfid. 1° Sodium Hydrorid Test.-NaOH = a yellow ppt. of mer- curic oxid, HgO, insoluble in excess: HgCl2 +2NaOH -HgO +2NaCl + H2O. Mercuric Oxid. INORGANIC BASES AND ACIDS. 41 2° Potassium lodid Test.-KI=a red ppt. of mercuric iodid,. Hgl2, soluble in excess of KI and HgCl2: HgCl2 +2KI = HgI2 +2KC1. Mercuric Iodid. 39 Ammonia Test.-NH4OH = a white ppt. of mercuric ammonium chlorid, NH2HgCl: HgCl2 +2NH4OH = NH2HgCl +NH4C1+2H2O. Mercuric Am- monium Chlorid. 37- Bismuth. 1° H2S in acid solution = a brown ppt. of Bi2S3, insoluble in (NH4)2S: 2Bi (NO3)3 + 3H2S = Bi2S3 + 6HNO3. Bismuthic Sulfid. 2° Potassium Iodid Test.-KI = a greenish-brown ppt. of Bil3, soluble in excess: Bi(NO3)3 +3KI=BiI3 +3KNO3. Bismuth iodid. 3° Chromate Test.-K2CrO4 = a yellow ppt. of Bi2(CrO4)3r 2Bi(NO3)3 +K2CrO4=Bi2(CrO4)3 +6KNO3. Bismuth Chromate. 38. Copper. Precipitated from acid solutions by H2S = a brownish-black ppt. of CuS, soluble in KCy: CuSO4 +H2S = CuS +H2SO4. Copper Sulfid. 42 QUALITATIVE CHEMICAL ANALYSIS. 1° Ammonia Test.-NH4OH=ablue ppt. soluble in excess to a dark-blue liquid: CuSO4 +2NH4OH = Cu(OH)2 + (NH4)2SO4 and CuSO4+4NH4OH=Cu(NH4)2(NH2)2SO4+4H2O. Ammonio-cupric Sulfate. 2° Sodium Hydrorid Test.-NaOH=a blue ppt., becoming black, CuO, on boiling. CuSO4 +2NaOH=Cu(OH)2 +Na2SO4 Copper Hydroxid. and Cu(OH)2 +heat = CuO + H2O. 3° Ferrocyanid Test.-K4FeCye = a brown ppt. of Cu2FeCye, insoluble in dilute acids: 2CuSO4 +K4FeCy6=Cu2FeCy6 +2K2SO4. Copper Ferrocyanid. 4° Borax-bead Test.-In 0 flame = green; blue when cold. 39. Arsenic. Precipitated from acid solutions by H2S = a yellow ppt. of AS2S3: As2O5 + 5H2S=As2S3 + 5H2O + S2. Arsenous Sulfid. Upon boiling and passing an excess of H2S through the solution, As2S5 is pptd. 1° Ammonio-Silver-nitrate Test.-AgNO3 in NH4OH solu- tion = a reddish-brown ppt. of Ag3AsO4. This is the differentiating test from arsenosum, which com- pare. INORGANIC BASES AND ACIDS. 43 40. Arsenous. Precipitated from acid solutions by H2S = a yellow ppt. of As2S3, soluble in (NH4)2S, and reprecipitated by HC1: 2As2O3 +6H2O = 4H3AsO3 and 4H3AsO3 +6H2S=2As2S3 +12H2O. Arsenous Sulfid. 1° C opper-sulphate Test.-In neutral solutions CuSO4 = a pale-green ppt. of CuHAsO3 (Scheele's green), soluble in NH40H z H3AsO3 +CuSO4 +2NH40H = CuHAsO3 + (NH4)2S04 +2H2O_ Copper Arsenite. 2° Ammonio-Silver-nitrate Test.-AgNO3 in NH40H solu- tion = yellow ppt. Ag3AsO3 (silver arsenite): H3AsO3 +3AgNO3 = Ag3AsO3 + 3HNO3. 3° Charcoal Test.-Heated on charcoal, arsenic gives a white incrustation and a garlicky odor. 4° Apply both Marsh's and Fleitmann's tests. Marsh's Arsenic Test.-1Generate hydrogen with dilute H2SO4 and metallic zinc in a bottle furnished with a jet and funnel-tube. After the gas has been given off in sufficient quantity to expel all the air contained in the bottle, the gas is ignited and the arsenical solution introduced through the funnel-tube. The yellow hydrogen flame is at once changed to a bluish1 flame characteristic of arsenic, and which emits a garlicky odor. If a piece of cold porcelain is held in this flame, a brown- ish-black spot of metallic arsenic is deposited upon it. (This is called an arsenic-spot.) The zinc and sulfuric acid used for generating the hydrogen must both be free from arsenic. 44 QUALITATIVE CHEMICAL ANALYSIS. Marsh's test is based on the formation of arsine gas, AsII3, the product of the action of nascent hydrogen upon arsenic in an acid medium: 6Zn +6H2SO4 +AS2O3 = 2AsH3 +6ZnSO4 +3H3O. Marsh's test, further, is used to differentiate between arsenic and antimony in a solution; for instance, antimony produces the same kind of spot as arsenic, but the arsenic spots dissolve readily when treated .with a few drops of a hypochlorite or euchlorin solution, while the antimony spots are not affected. 5° Fleitmann's Test for Arsenic.-A fragment of metallic zinc or aluminum is placed in a test-tube with some KOH solution, and a small quantity of the arsenical solution is added. Heat the mixture and place over the mouth of the tube a cap of paper moistened with a solution of AgNO3. The arsine which is evolved acts upon the silver nitrate, reducing it to metallic silver, which is shown by the development of a dark stain on the paper. The advantage of this test lies in the fact that stibine is not evolved in alkaline solutions as in the case of Marsh's test, .and hence only arsenic reacts in the manner described: Zn +2K0H - K2Z11O2 +H2; Potassium Zincate. H3AsO3 +3H2 = AsH3 +3H2O; Arsine. AsH3 +6AgNO3 +3H2O =3Ag2 +H3AsO3 +6HNO3. Metallic Silver. 41. Cadmium. Precipitated from acid solution by H2S = yellow ppt. CdS insoluble in (NH4)2S but soluble in HNO3. This ppt. will form INORGANIC BASES AND ACIDS. 45 in the presence of potassium cyanid (distinction from copper): CdCl2+H2S=CdS+2HCl. Cadmium Sulfid. 1° Ammonia Test.-NH4OH = a white ppt. of Cd(OH)2, soluble in excess: CdCl2 +2NH4OH = Cd(OH)2 +2NH4C1. Cadmium Hydroxid. 2° Sodium-hydroxid Test.-NaOH = a white ppt. of Cd(OH)2, insoluble in excess: CdCl2 +2NaOH = Cd(OH)2 +2NaCl. 3° Apply sodium-carbonate test, paragraph 25. A brown coating of CdO; no metallic bead. 42. Antimony. Precipitated from acid solutions by H2S = an orange ppt. of Sb2S3, soluble in (NH4)2S, and reprecipitated by HCL The ppt. is not soluble in (NH4)2CO3 solution (distinction from arsenic): 2SbCl3 +3H2S=Sb2S3 +6HC1. Antimonic Sulfid. 1° Copper Test.-Metallic copper in acid solutions of anti- mony receives a grayish deposit of antimony; when this is heated in a test-tube a white ring of Sb2O3 forms in the tube, near the copper: CU5 +Sb4 +3O2 = Cu5 + 2Sb2O3. Metallic Copper. 46 QUALITATIVE CHEMICAL ANALYSIS. 2° Water Test.-Slightly acid solutions of SbCl3 poured in water = a white ppt. of (SbOCl)2 +Sb2O3, soluble in tartaric acid: 4SbCl3 +5H2O = (SbOCl)2 +Sb2O3 + 10HC1. Powder of Algaroth. 3° Apply Marsh's test. 43- Stannic Salts. H2S precipitates from acid solutions SnS2 = a yellow ppt. slowly soluble in (NH4)2S, and reprecipitated by HC1: SnCl4 +2H2S=SnS2 +4HC1: Stannic Sulfid. 1° Sodium-hydroxid Test.-NaOH = white ppt. Sn(OH)4: SnCl4 +4NaOH =Sn(OH)4 +4NaCl. Stannic Hydroxid. 2° Molybdenum Test.-(NH4)2MoO4 = no blue coloration (dis- tinction from stannous). 44. Stannous Salts. Precipitated by H2S from acid solution as SnS = a brown ppt. slowly soluble in (NH4)2S; reprecipitated by HC1 = a yellow ppt. of SnS2: SnCl2+H2S=SnS+2HCl; 1° Sodium-hydroxid Test.-NaOH = a white ppt. of Sn(0H)2, soluble in excess of reagent: SnCl2 +2NaOH = Sn(OH)2 +2NaCl; Sn(OH)2 +2NaOH=Na2SnO2 +2H2O. Sodium Stannite. INORGANIC BASES AND ACIDS. 47 2° Mercuric Test.-HgCl2 produces in solutions of stannous salts a white ppt. of Hg2Cl2 which darkens on boiling, being reduced to Hg: SnCl2 +HgCl2 = SnCl4 +Hg. 3° Molybdenum Test.-(NH4)2MoO4 = a blue ppt. (distinction from stannic tin). 45. CHART FOR THE SEPARATION OF GROUP HI. 18. Evaporate filtrate from Group II, or if Groups I and II were found to be absent, a separate portion of the original solution is taken. As the filtrate plus the washings from Group II are quite voluminous, it is desir- able to carry the evaporation down to one-sixth or less of the original bulk. Here also account must be taken of the fact whether or not organic sub- stances like citric, tartaric, or malic acid, glycerin, etc., be present; also the presence of phosphates and oxalates should be determined, as these interfere. If iron has been detected in the preliminary tests, add a few drops of strong IINO3 and boil well, next add a little solution of NH4C1 and excess of NH4OH, boil and filter. 19. Precipitate. Fe, Al, Cr, Mn (traces). Insoluble phosphates and oxalates. (Dissolve some original substance in strong HNO3, boil, pour into some solution of ammonium molybdate, and boil. Yellow coloration or pre- cipitate indicates insoluble phos- phates.) See paragraph 81. 24. Filtrate. Zn, Co, Ni, Mn. Add (NH4)2S: all the sulfids are ppt'd Dissolve ppt. in HC1, add excess of NH4OH, acidify with HC2H3O2, pass H2S through the solution, and filter 25. Precipitate. 28. Solution. Ifwhite=Zn. If Mn. black =CO or Ni. Fuse with a fusing Dissolve in HC1; mixture; green add sol. KCy residue =Mn. and solution of chlorinated soda, boil, and filter. • Fuse ppt. with 4 times its weight of a mixture of Na2CO3 and KN03 in a crucible or on a platinum foil, treat mass with boiling-hot water, and filter. 20. Insoluble. Fe. Pour HC1 over the ppt. on filter and divide the fil- trate into two portions: to (1) add K4FeCy6= blue ppt. = Fe; to (2) add KCyS= red color =Fe. 21. Soluble. Al, Cr. Divide this sol. into two por- tions and test for Al and Cr. 26 Precipitate.. 27. Solution. N i. Co. Confirm both by borax bead. 23. Acidify with HC1, add a large excess of NH4OH and shake well; white ppt. = Al. 22. Acidify with HC2H3O2; to one por- tion add excess of AgNO3 = red ppt. = Cr; to another portion add some sol. Pb(C2H3O2)2= yellow ppt. = Or. 48 QUALITATIVE CHEMICAL ANALYSIS. 46. Observations on Group III. The object of evaporating the filtrate from Group II is to dissipate the H2S and thus prevent the formation of (NH4)2S, which in turn would precipitate the iron, cobalt, and nickel, etc. ; Attention here is called to organic substances mentioned in No. 18, paragraph 45. The precipitation of iron, aluminum, and chromium as hydroxids can only be accomplishea in the absence of organic acids and other organic substances, like sugar or glycerin, con- taining several of the hydroxyl groups. Therefore, if these be detected in the preliminary tests, evaporate the H2S filtrate to dryness, heat the residue with a few drops of strong HNO3 (thus decomposing organic substances), dissolve the residue in HC1, and proceed in the usual way. Should organic substances be absent, boil the solution with HNO3 to oxidize the ferrous salts to the ferric state (thus insuring the complete precipitation of iron by ammonia). Excess of HNO3 should be avoided. The NH4OH (which should be added until the solution smells strongly of NH3) precipitates Fe2(OH)6, A12(OH)6, and Cr2(OH)e, with a trace of manganese. Zinc, manganese, cobalt, and nickel, which are also precipitated, form soluble hydroxids which dissolve in the excess of NH4OH, and are found in the filtrate. Although the manganese is soluble in the excess of NH4OH, during the heating and subsequent filtration employed in the separation of the Al and Cr, it absorbs oxygen, and from man- ganous becomes oxidized to mangano-manganic oxid (Mn2O3), which, being insoluble in NH4OH, is precipitated together with the Fe, Al, and Cr. The object of adding NH4C1 before the group reagent NH4OH is to prevent the precipita- tion of Mg(OH)2, which forms a soluble double compound, MgCl2.2NH4Cl. The solution of NH4C1 also facilitates the INORGANIC BASES AND ACIDS. 49 •complete solution of Co, Ni, Zn, and Mn in the excess of NH4OH. To completely precipitate the Al and Cr, the mixture must be boiled. 47. Notes on Group III. 19. When dried and fused the hydroxids lose water and :are converted into oxids, Fe2O3, A12O3, and Cr2O3. When treated with water and filtered, the Fe2O3 remains as an insoluble reddish-brown powder on the filter. The A12O3 combines with the alkaline fusing mixture to form a soluble potassium .aluminate thus: A12O3 +K2CO3 = 2KA1O2 +CO2. The Cr2O3 likewise unites with the fusing mixture in the presence of oxi- dizers, according to the following reaction: Cr2O3+O3 = 2CrO3; then 2CrO3+2K2CO3 = 2K2Cr2O4+2CO2. The oxidizer in this ■case is KNO3; KC103 acts similarly. • When the ppt. is fused, the Mn is oxidized to green potas- •sium manganate (K2MnO4); this being soluble in the water interferes with detection of the Al and Cr. This green solu- tion is therefore treated with alcohol, drop by drop, until the green color is discharged. The alcohol is reduced to aldehyd, which in turn reduces the manganese to mangano-manganic oxid (Mn2O3), which then precipitates and should be filtered out before testing for Al and Cr. 21. Aluminate of potassium (KA102) is colorless; chromate •of potassium (K2CrO4) is yellow; manganate of potassium (K2MnO4) is green, but after boiling in water it becomes pink. 22. The portion of the solution reserved for the detection of Cr will be yellow from the presence of K2CrO4, indicating Cr. The object of acidifying the solution with acetic acid is to convert the carbonates into acetates; if this were not done, brown argentic oxid and white plumbic carbonate would be precipitated. 23. Neutralization is done with HC1, which at the same time forms aluminum chlorid, and from which NH4OH throws 50 QUALITATIVE CHEMICAL ANALYSIS. out aluminum hydroxid as a gelatinous precipitate, Al2(OH)6r insoluble in excess. 24. The metals are precipitated as sulfids, their identity being indicated by the color of the precipitate, thus: MnS, flesh-colored; ZnS, white; CoS and NiS, black. Excess of (NH4)2S should be carefully avoided, as it dissolves some of the NiS (in which case the filtrate is brownish black). A black filtrate is evaporated and the precipitate in the form of black NiS is reclaimed. HC1 dissolves all the sulfids; the NH4OH being added to neutralize the HC1, the solution next being re-acidified with HC2H3O2, and H2S passed through the solution. Acetic acid is used in this case, as stronger acids would prevent the precipitation of ZnS, NiS, and CoS. 25. If the solution is not black, Co and Ni need not be sought for. If the precipitate is white=Zn. The HC1 converts the hydroxids of Co and Ni into chlorids, and the KCy forms double cyanid salts of Co and Ni; on the addition of the chlorinated soda the insoluble Ni is left, while the Co dissolves. 26 and 27. See borax-bead reactions for cobalt and nickel. 28. The fusing mixture is KNO3 and Na2CO3. SPECIAL TESTS FOR METALS OF GROUP III. (Alkali Sulphid Group.) To be applied to separate portions of the solution. 48. Ferric Salts. (NH4)2S precipitates from alkaline solutions (FeS+S), a black ppt.; the FeS is soluble in HC1: Fe2Cl6 +3(NH4)2S = 2FeS+S +6NH4C1. Ferrous Sulfid. INORGANIC BASES AND ACIDS. 51 1° K^FeCys Test.-K4FeCy6 gives a deep blue ppt. of Fe7Cyi8 or Fe4(FeCy6)3, insoluble in acids: 2Fe2Cle +3Ix4FeCye-Fe4(FeCye)3 + 12KC1. Ferric Ferrocyanid. 2° K^FeCys Test.-K3FeCy6 gives a brown solution: Fe2Cl6 +2K3FeCy6=Fe2(FeCy6)2 +6KC1: 3° Hydroxid Test.-Both NaOH and NH4OH = brown ppt., insoluble in excess: Fe2Cl6 +6NH4OH =Fe2(OH)6 +6NH4OH. Ferric Hydroxid. 4° Suljocyanid Test.-KSCy = blood-red coloration: Fe2Cl6 +6KSCy=Fe2(SCy)6 +6KC1. Ferric Sulfocyanid. 49. Ferrous Salts. (NH4)2S precipitates from alkaline solutions FeS soluble in HC1 and quickly oxidized in the solution to FeSO4: FeCl2 + (NH4)2S = FeS +2NH4C1. Ferrous Sulfid. 1° Ferrocyanid Test.-K4FeCye = white ppt. (distinction from ferric), rapidly becoming blue: 2FeCl2 + 2K4FeCy 6 = 2FeK2FeCy6 + 4KC1. 52 QUALITATIVE CHEMICAL ANALYSIS. 2° Ferricyanid Test.-K3FeCy6 = deep-blue ppt. insoluble in acids: 3FeCl2 + 2K3FeCye + Fe3Fe2Cyi2 +6KC1. Ferrous Ferricyanid. 3° Sulfocyanid Test.-No red coloration (distinction from ferric). 50. Cobalt In alkaline solutions gives a black ppt. of CoS with (NH4)2Sl Co(NO3)2 + (NH4)2S=CoS +2NH4NO3. Cobalt Sulfid. 1° Ammonia Test.-NH40H = a blue ppt. of Co(OH)2 soluble- in excess to a brown solution, and reprecipitated by NaOH: Co(NO3)2 +2NH4OH = Co(OH)2 +2NH4NO3. Cobalt Hydroxid. 2° Borax-head Test gives a blue bead. 3° Cyanid Test.-KCy=a brown ppt. of CoCy2 soluble in excess on boiling and not precipitated by chlorinated soda solution (distinction from nickel). 4° Sodium Hydroxid Test.-NaOH = a blue ppt. of Co(OH)2r changed to red on boiling. 51. Nickel. Precipitated from alkaline solutions by (NH4)2S = a black ppt. of NiS, nearly insoluble in dil. HC1: NiSO4 + (NH4)2S-NiS + (NH4)2SO4. Nickel Sulfid. INORGANIC BASES AND ACIDS. 53 1° Sodium-hydroxid Test.-NaOH = a green ppt. insoluble in excess, not changed by boiling: NiSO4 +2NaOH=Ni(OH)2 +Na2SO4. Nickel Hydroxid. 2° Ammonia Test.-NH4OH gives a precipitate similar to 1°,. but soluble in excess of the reagent, forming a violet-colored solution. 3° Cyanide Test.-KCy = a pale green ppt. soluble in excess. When boiled with chlorinated soda solution = a black ppt.: NiSO4 +2NH4OH = Ni(OH)2 + (NH4)2SO4. 4° Borax-bead Test.-Purplish brown hot; pinkish brown cold. 52. Zinc. Precipitated in presence of NH4C1 from alkaline solutions by (NH4)2S as ZnS = a white ppt. soluble in HC1: ZnSO4 + (NH4)2S = ZnS + (NH4)2SO4. '-V ' Zinc Sulfid. 1° Cobalt Test.-Heat a portion of the solution on char- coal with a drop or two of Co(NO3)2 solution = a green mass which is infusible. 2° Ferrocyanid Test.-K4FeCye gives a white gelatinous ppt. of Zn2FeCye insoluble in diluted acids: 2ZnSO4 +K4FeCye = Zn2FeCye +2K2SO4. 1 54 QUALITATIVE CHEMICAL ANALYSIS. 53. Aluminum. (NH4)2S precipitates from alkaline solutions A12(OH)6 insoluble in excess: A12(SO4)3 +3(NH4)2S +GH2O = A12(OH)6 +3(NH4)2SO4 +3H2S. Aluminum Hydroxid. 1° Phosphate Test. - Na2HPO4 + NH4OH + HC2H3O2 = a white ppt. of A1PO4 insoluble in hot HC2H3O2, but soluble in HC1: A12(SO4)3 +2H3PO4 = 2A1PO4 +3H2SO4. Aluminum Phosphate* 2° Hydroxid Test.-BothNH4OH and NaOH give a gelatinous white ppt. soluble in excess, with the former only slightly soluble; Al2(SO4)3+6NaOH = Al2(OH)6+3Na2SO4. Aluminum Hydroxid. 3° Cobalt Test.-Co(NO3)2 added to a portion heated on charcoal gives an infusible blue mass. 54. Manganese. Precipitated from alkaline solutions by (NH4)2S as MnS, a flesh-colored ppt. soluble in diluted HC1 or HC2H3O2: MnSO4 +2(NH4)2S = MnS +2(NH4)2SO4. Manganese Sulfid. 1° Lead Test.-PbO2 heated with some of the substance and HNO3 (until free from nitrous fumes) and poured into H2O gives a purple solution of permanganate: INORGANIC BASES AND ACIDS. 55 2MnS04 +4HN03 +3PbO2 =H2Mn2O8 +2PbSO4 +Pb(NO3)2 +N2O3 +H20. Permanganic Acid. 2° Alkaline-hydroxid Test.-NaOH or KOH = a white ppt. of Mn(OH)2, which becomes brown upon heating: MnS04 +2NaOH = Mn(OH)2 +Na2SO4. Manganese Hydroxid. 3° Carbonate Test.-Heated on a platinum wire with some Na2CO3 gives a green mass. " 4° Borax-bead Test.-Bead in 0 flame is purple-colored. > 55. Chromium. (NH4)2S precipitates from alkaline solutions Cr2(OH)6 = a green ppt. soluble in diluted HC1: Cr2(SO4)3 +3(NH4)2S +6H2O=Cr2(OH)6 +3(NH4)2SO4 +3H2S. Chromium Hydroxid. 1° Sodium - hypochlorite Test.- Chlorinated soda solution (NaClO +NaCl) boiled with an alkaline chromium salt gives a yellow solution of sodium chromate, (Na2CrO4). 2° Sodium-hydroxid Test.-NaOH = a bluish-green ppt. of Cr2(OH)6 soluble in excess, and reprecipitated on boiling: Cr2(SO4)3 +6NaOH = Cr2(OH)6 +3Na2SO4. Chromium Hydroxid. 3° Borax-bead Test.-The bead is emerald-green in color. 56 QUALITATIVE CHEMICAL ANALYSIS. 56. CHART FOR THE SEPARATION OF GROUP IV. 29. To the alkaline filtrate from Group III add some solution of (NH4)2C()3, warm and allow to rest a few minutes; if a precipitate occurs, it may contain Ba, Sr, Ca. 30. Collect, wash, and dissolve it on the filter with a small quantity of acetic acid. To the filtrate add some solution of K2CrO4; if a precipitate occurs, filter. 31. Precipitate. Ba = yellow ppt. Confirm by dissolving ppt. in HC1 and flame test. Green-colored flame = Ba. 32. Solution. Sr, Ca. Add to this some dil. H2SO4 (1:50), shake well and filter. 33. Precipitate. Sr. Confirm by moistening the ppt. with HC1 and applying flame test. Crimson-colored flame = Sr. 34. Solution. Ca. Neutralize with NH4OH. add (NH4)2C2O4: a white ppt. = Ca. 57. Observations on Group IV. 29. The metals of this group are precipitated as carbonates, thus: BaCO3, SrCO3, CaCO3. Magnesium carbonate is not pre- cipitated here on account of its being present as a double magnesium-ammonium soluble compound (MgCl2.2NH4Cl.) The solution with the precipitated carbonates should only be warmed, not boiled. If the mixture be boiled, the precipi- tated carbonates are decomposed into chlorids through the presence of the magnesium-ammonium compound, and may later be mistaken for magnesium when Na2HP04 is added for the detection of that metal. The above-mentioned decomposition into chlorids is ex- plained by the following two reactions: (1) CaCl2 + (NH4)2CO3 = CaCO3 +2NH4C1. (2) CaCO3 +2NH4C1 = CaCl2 + (NH4)2C03. INORGANIC BASES AND ACIDS. 57 58. Notes on Group IV. 30. When the precipitated carbonates are treated with acetic acid, acetates of the metals are formed with the evolu- tion of CO2. When neutral potassium chromate is added, barium is separated as yellow barium chromate (BaCrO4). 31. See paragraph 59. 32. The exact separation of the calcium and strontium is tedious. The following simple method based on the solubilities in water of SrSO4 (1 in 7000) and CaSO4 (1 in 400) is usually employed: To a small portion of the filtrate add some satu- rated solution of CaSO4 and set the mixture aside for some time. If strontium be present, SrSO4 (a white ppt.) will be obtained. To another portion add some very dilute H2SO4 (1 in 50) and set aside for complete deposition of SrSO4 (this will contain some CaSO4). 33. Apply the flame test for the strontium (crimson flame). 34. If the least trace of calcium be present in the filtrate, a white precipitate of calcium oxalate insoluble in water and acetic acid is obtained on the addition of ammonium oxalate. SPECIAL TESTS FOR METALS OF GROUP IV. (Carbonate Group.) To be applied to separate portions of the solution. 59. Barium. Precipitated from alkaline solutions (previously heated) by (NHVhCOs, =BaCOs; soluble in acids: BaCl2 + (NH4)2CO3 +2NH4CI = BaCO3. Barium Carbonate. 58 QUALITATIVE CHEMICAL ANALYSIS. 1° Suljate Test.-K2SO4 or CaSO4 = a white ppt. of BaSO4 insoluble in acids: BaCl2 +K2SO4 = BaSO4 +2KC1. Barium Sulfate. 2° Chromate Test.-K2CrO4 = a yellow ppt. of BaCrO4 in- soluble in HC2H3O2: BaCl2 +K2CrO4 = BaCrO4 +2KC1. Barium Chromate. 3° Oxalate Test. - (NH4)2C2O4 = a white ppt. soluble in HC2H3O2: BaCl2 + (NH4)2C2O4 = BaC2O4 +2NH4C1. Barium Oxalate. 4° Flame Test.-Barium salts heated with HC1 on a platinum wire=a green flame. 60. Strontium. Precipitated from hot alkaline solutions by (NH4)2CO3 = a white ppt. soluble in acids: Sr(NO3)2 + (NH4)2CO3 = SrCO3 +2NH4NO3. Strontium Carbonate. 1° Chromate Test.-K2Cr2O7=no precipitate except in very concentrated solutions. 2° Sulphate Test.-K2SO4 or CaSO4 = a white ppt. of SrSO4 (which forms very slowly, and is more soluble than BaSO4): Sr(NO3)2 +CaSO4 = SrSO4 +Ca(NO3)2. INORGANIC BASES AND ACIDS. 59 3° Flame Test.-Strontium salts heated with HC1 on a platinum wire = a crimson-red flame. 61. Calcium. Precipitated from hot alkaline solutions by (NH4)2C03. = a white ppt. of CaCO3 soluble in acids: CaCl2 + (NH4)2CO3 = CaCO3 +2NH4C1. Calcium Carbonate. 1° Oxalate Test.-(NH4)2C2O4 = a white ppt. of CaC2O4 nearly insoluble in HC2H3O2: CaCl2 + (NH4)2C2O4 = CaC2O4 +2NH4C1. Calcium Oxalate. 2° Suljate Test.-K2SO4 in concentrated solutions = a white ppt. of CaSO4.: CaCl2 +K2SO4=CaSO4 +2KC1. Calcium Sulfate. 62. GROUP V. 35. Divide the filtrate from Group IV into two portions^ one larger than the other. To the smaller portion add seme- NH4OH and Na2HPO4. A white precipitate indicates mag- nesium. 36. Evaporate the larger portion to dryness and ignite if no residue, K, Na, and Li are absent. If residue, dissolve it in a few drops of water, place on a watch-glass, acidulate* with HC1 and add solution PtCl4. A yellow ppt. = potas- sium. 60 QUALITATIVE CHEMICAL ANALYSIS. 37. Heat a little of the original substance or solution with sol. of KOH, NaOH, or Ca(OH)2. Odor of ammonia indicates ammonium. 38. Apply a little of the solution from 36, or some of the original substance on a platinum wire, to the colorless gas fame and observe 63. The Color of the Flame. Yellow . Sodium compounds. Red . Calcium or lithium compounds. Crimson . Strontium compounds. Violet (through blue glass). . Potassium compounds. Blue . Lead, arsenic, antimony. Green . Barium, copper, or boric acid. Greenish white . Zinc. 6 y. Observations and Notes on Group V. The filtrate from Group IV contains only the salts of Mg, IK, Na, Li, and NH4. 35. The object of adding NH4OH before the Na2HPO4 is to render the ppt. less soluble in water. If magnesium be present, it is indicated by a crystalline precipitate of ammonio-magnesium phosphate (MgNH4PO4). This precipitate appears only on standing. Any non- orystalline precipitate is calcium which may have escaped from the previous group. 36. The residue in this case is ignited to dissipate the NH4 compounds, since these form insoluble double chlorids with platinic chlorid (PtCl4). The ignited residue may contain Mg, if its presence has been detected in the smaller quantity of the liquid. The yel- low precipitate formed with K is a double chlorid of potassium and platinum (2KCl.PtCl4). INORGANIC BASES AND ACIDS 61 With sodium a corresponding soluble salt is formed which gives an intense yellow coloration to the flame. SPECIAL TESTS FOR METALS OF GROUP V. To be applied to separate portions of the solution. 65. Magnesium. Precipitated from its alkaline ammonium-chlorid solution by Na2HPO4 as MgNH4PO4 = a white ppt., from concentrated solutions, and a crystalline ppt. from dilute solutions: MgSO4 +NH4OH +Na2HPO4 = MgNH4PO4 +Na2SO4 +H2O. Ammonio-magnesium Phosphate. 1° Alkaline-hydroxid Test.-Both NaOH and NH4OH = a white ppt. of Mg(OH)2 soluble in NH4C1: MgS04 +2NaOH = Mg(OH)2 +Na2SO4. 2° Charcoal Test.-Heated on charcoal with a drop or two of Co(NO3)2 solution, leaves a pinkish mass. 3° Carbonate Test.-Sodium carbonate produces a white ppt. of basic magnesium carbonate, soluble in NH4C1. 66. Potassium. 1° Alkaline-tartrate Test.-NaHC4H406 = a white crystalline ppt. of KHC4H40e (in concentrated solutions only). This is a distinguishing test between potassium and sodium, the latter not giving a ppt. with alkaline tartrate: KNO3 +NaHC4H4O6 = KH4H4O6 +NaNO3. Potassium-hydrogen Tartrate. 62 QUALITATIVE CHEMICAL ANALYSIS. 2° Platinum-chlorid Test.-PtCl4 = a yellow ppt. of K2PtCU soluble in excess of water (distinction from Na): 2KCl+PtCl =K2PtCl6. Double Potassio- platinic Chlorid. 3° Sodium-Cobaltic-nitrite Test.-NaNO2.Co(NO2)2 in pres- ence of HC2H3O2 = a yellow crystalline ppt. 4° Flame Test.-Potassium salts heated with HC1 on a platinum wire = a violet coloration when viewed through a blue glass. 67. Sodium. 1° Alkaline-tartrate Test-NaHC4H4O6 = no precipitate (dis- tinction from potassium). 2° Platinum-chlorid Test.-PtCl4 = no precipitate with sodium salt (distinction from potassium). 3° Antimony Test.-K2Sb2O6 = a white crystalline ppt. of Na2Sb2Oe (metantimonate) in neutral solutions only and on vigorous shaking: 2NaCl +K2Sb2O6=Na2Sb2O6 +2KC1. 4° Flame Test.-Sodium salts with HC1 heated on platinum wire give intense yellow coloration to the flame (invisible through blue glass). 68. Lithium. 1° Phosphate Test.-Na2HPO4 in boiling solutions = a white ppt. of Li3PO4: 3LiCl +Na2HPO4 = Li3PO4 +2NaCl +HC1. Lithium Phosphate. INORGANIC BASES AND ACIDS. 63 2° Carbonate Test.-Na2CO3 in concentrated solutions = Li2CO3: 2LiCl +Na2CO3 = Li2CO3 +2NaCl. Lithium Carbonate. 3° Flame Test.-Lithium salts heated with HC1 on a plati- num wire = a bright-red flame. 69. Ammonium. 1° AIkaline-tartrate Test.-NaHC4H406 = white ppt.: NH4C1 +NaHC4H4O6 = NH4HC4H4O6 +NaCl. . , , » Ammonium Acid Tartrate. 2=.Flatinic-chlorid Test.-PtCl4 = a yellow ppt. of (NH4)2PtCle (in concentrated solutions): 2NH4C1 +PtCl4 = (NH4)2PtCl6. Double Ammonio-. platinic Chlorid. 3° Hydroxid Test.-Either NaOH or Ca(OH)2 heated with some of the solution gives off NH3 (detected by the smell). This vapor turns red litmus paper blue: NH4C1 + KOH = NH3 + KC14- H2O. Gas. Hold a glass rod moistened with HC1 over the mouth of the test-tube: white fumes of NH4C1 are formed: NH3+HC1 = NH4C1. Ammonium Chlorid. 4° Nessler's Test.-Nessler's reagent (made from HgCl2+KI till ppt. dissolves, then NaOH in excess) gives a yellow or brownish ppt. of NHg2I (di-mercuric ammonium iodid). NH3 +2HgI2 +3NaOH = NHg2I +3NaI +3H2O. 64 QUALITATIVE CHEMICAL ANALYSIS. 70. CHART FOR THE SEPARATION OF INSOLUBLE PHOSPHATES. 39. If the precipitate in Group III contains phosphates (proved by ammonium molybdate test), dissolve the pre- cipitate in a very small quantity of HC1, add someNaC2H3O2 and then some solution Fe2Cl6. Boil for five minutes and filter. (The ppt. contains the insoluble phosphates of iron, chromium, and aluminum.) The filtrate is tested for the ordinary metals of the third and fourth groups in the usual manner. Fuse the ppt. well with KNO3 and Na2CO3, treat with boil- ing water and filter. Test a portion of the filtrate for Cr with a solution of AgNO3; a red ppt. =Cr. The remainder of the fil- trate is next acidified with HC1, and an excess of NH4OH added; a white flocculent ppt. = Al. The residue on the filter is dis- solved with a few drops of hot aqua regia, diluted with water, and added to some KCyS solution; a blood-red coloration = Fe. 40. If the original substance is insoluble and was found to contain phosphates, employ the following chart: Boil some of the substance with a very small quantity of HCI, add cold NaOH in excess, filter. The residue will contain the iron and other insoluble phosphates. Digest with cold acetic acid and filter. Insoluble. Phosphates of Al, Cr, Co, Ni, Zn. Mn, Ba, Sr, Ca, Mg. Add Fe2Cl6, drop by drop, until a pale-reddish tint is obtained. Heat for some time and filter while hot. Soluble. FePO4. Reddish-white ppt. Insoluble. FePO4. Soluble. Members of Group III and IV to be proved in the ordinary way. Note.-The important insoluble (in water and acids) substances which may be found in the insoluble residues are: C, S, BaSO4, SrSO4, CaSO4, PbSO4, BbCl2. AgCl, CaF2, silica and silicates, and native oxids of Al, Cr, Fe, and Sn. Special tests should be applied to identify these. INORGANIC BASES AND ACIDS 65 71. Color of Borax Beads.-Borax, Na2B4O7, when ignited on a loop of a platinum wire forms a bead, known as borax bead, which when dipped in certain compounds or their solu- tions yields a colored glass useful for the detection of many of the metallic compounds, thus: In the Oxidizing Flame. In the Reducing Flame. Indicates Hot. Cold. Hot. Cold. Green Blue Blue Red Cu Blue Co Green Green Cr Red Yellowish Bottle-green Fe Amethyst Colorless Mn Purple-brown Pink-brown Reddish brown Y ellow Ni 72. PREPARATION OF A SOLUTION FOR ANALYSIS IN THE WET WAY. To confirm the results obtained by the dry examination of -all solid substances, except simple ones that yield positive re- sults in the dry way, the matter of getting these into solution becomes of importance. To bring into play the natural force called chemical affinity, substances must be brought into close contact with one another, and this condition can best be brought about in a solution. For analytical purposes all substances may be divided into four classes, as follows: 1. Substances soluble in water. 2. Substances insoluble in water but soluble in an acid. 3. Substances insoluble in an acid but soluble in a mixture of acids. 4. Substances decomposed by fusing with carbonates. Complex substances may contain compounds belonging to each of the above four classes. A small portion is heated with some water in a test-tube and filtered; the filtrate is now 66 QUALITATIVE CHEMICAL ANALYSIS. tested for compounds which may have gone into solution. The residue is next treated with an acid, the excess of the acid evaporated off, the substance diluted with water and filtered, and the filtrate tested for substances that may have been dissolved, etc. The order most frequently followed is: 1st, water; 2d, hydrochloric acid, dilute; 3d, HC1 concentrated: 4th, nitric acid, dilute; 5th, HNO3 concentrated; 6th, nitro- hydrochloric acid; 7th, sulfuric acid. In using acids as solvents care must be taken not to use them in excess; if, however, an excess has been used, evaporate the solution under a hood to drive off the excess of acid. If the acid is the proper solvent, very little of it will dissolve a large quantity of the substance. If, after going through the above-mentioned list of acid sol- vents, the substance still remains insoluble, it may consist of BaSO4, PbSO4, C, S, oxids of tin, silica and silicates, fluorids alumina and aluminates, Sb2O3 and Sb2O5, chrome iron ere,, some metaphosphates, arsenates, silver chlorid, etc. Fuse a small portion of the powder with about five times its bulk of a fusion mixture (Na2CO3+KNO3) in a small crucible (preferably platinum), extract the fused mass with water, and filter. Dis- solve what remains on the filter in HC1; if this does not effect solution, try HNO3. Note 1. If the preliminary examination shows absence of Pb, boil the powder with NaOH solution, thus avoiding the more difficult and tedious fusion. The action of the fusion mixture in the above operation is, generally speaking, to convert the base into an oxid or a carbonate, the acid of the substance combining with the Na and K as a corresponding salt. Note 2. It should be remembered that the excess of any acid solvents must be removed before proceeding to examine for metals of the second group; strong acids (a) decompose H2S into its elements and (6) prevent the precipitation of some of the metals. INORGANIC BASES AND ACIDS. 67 Above all it should be borne in mind that: (T) If the substance is solid, it must be finely powdered before effecting solution. (2) That each solvent should be tried first cold, and then, if required, hot. (3) The solution for analysis should be neutral or just slightly acid. If alkaline, neutralize with HNO3, any pre- cipitate produced being filtered off and examined separately. (4) Since cyanids, ferrocyanids, cobalticyanids, etc., greatly interfere with the ordinary processes of analysis, it is best to destroy them before proceeding, by evaporating some of the solution to dryness with H2SO4, whereby all the metals will be obtained as sulfates. (5) If the substance is a hard metal or alloy, treat it as under " Alloys and Hard Metals ". 73. ALLOYS AND HARD METALS. Procedure.-Cut the alloy into very small pieces, or file off 2 grams of it, or hammer it out flat so as to expose the largest possible surface to the action of the acid. Heat about 2 grams of the thus-prepared substance with about 40 c.c. of strong HN03 in a capsule, evaporate to small bulk to remove excess of acid, dilute with II2O, and filter. Insoluble. SnO2.and Sb2O5 (as hydrox.ds or as arsenates). [Also possibly Bi as arsenate or phosphate, and Au and Pt 4] Digest with zinc and dilute HC1. Test the evolved gases for arsine by the AgNO3 test. Residue on the zinc may consist of the remaining metals. Boil for some time with strong HC1 under hood, and filter. Soluble. Apply the usual group reagents and identify the metals in the groups. Insoluble. Sb [Bi, Au, Pt.] Digest with yellow (NH4)2S; Sb dissolves as sulfo-salt. Evaporate solution to dryness. Orange-red residue = anti- mony. Soluble. SnCL. Add HgCl2. White ppt., turning gray on heating = tin. 68 QUALITATIVE CHEMICAL ANALYSIS. Name. Soluble in Water. Soluble in, or Decomposed by, Acids. Insoluble. Carbonates Acid carbonates of Ba, Sr, Pb, Mn, Mg, Fe", and Ca, and alkaline carbonates. All carbonates are decomposed with evolution of CO2. Sulfates Most sulfates. (Ag2SO4 is diffi- cultly soluble.) Some basic sulfates. Suifates of Pb, Ba, Sr, and Ca, and red chromic sulfate. Nitrates Most nitrates (a few basic ni- trates excepted). A few basic nitrates which are readily soluble in dilute HNO3. Chlorids Most chlorids. A few oxychlorids. (BiOCI and SbOCl.) Chlorids of Pb, Hg', Ag, and Cu2Cl2. Bromids Most bromids. Cu2Br2 in HC1. Bromids of Hg', Ag, and Pb. lodids Most iodids. Hgl2, Hg2I2 (= Hgl2 + Hg), Pbl2, Cu2I2 decomposed by HNO3 with evolution of I. lodids of Ag, Hg', Hg", Pb, and Cu'. Chlorates All chlorates. • Sulfids Alkaline and alkaline-earthy sul- fids. MgS and CaS very slight- ly soluble. All other suffids are decomposed by HC1 (H,S being evolved), or by HN()3, or aqua regia, with separation of S. Phosphates Alkaline phosphates only. Remainder are soluble. Chromates Alkaline chromates and chro- mates of Mg, Zn, Ca, Sr, Fe!V, and Cu. Chromates insoluble in water dissolve in acids (evolving chlorin in concentrated HC1). Ignited lead chromate. 74- SOLUBILITIES.-Table Showing the Solubility of the More Commonly Occurring Salts. INORGANIC BASES AND ACIDS. 69 75. THE IDENTIFICATION OF ACIDS AND ACIDULOUS RADICALS. Acids are divided into two classes: (a) Inorganic,(6) Organic. The tests applied below are intended to be applied to salts of the alkaline metals, for only in such combination can reli- able results be obtained in testing for the acids. Therefore if the acid or its radical is not in combination with an alka- line metal, it is a general rule to convert it into a salt of sodium, by boiling with NaOH. The ppt., if any, should be separated by filtration and the filtrate tested. (a) If the salt is soluble in water and neutral or alkaline in reaction, the boiling with NaOH is generally not needed. (6) If the substance is insoluble in water but soluble in acids, boil a portion of the solid with a strong solution of sodium carbonate, filter, and use the filtrate. (c) If the substance is insoluble, treat as described for the preparation of the solution for analysis of insoluble sub- stances, using the filtrate, which is neutralized with NH40H. (d) In those cases where the metal present is one whose hydroxid is soluble, and which cannot in consequence be removed by treatment with NaOH, it is necessary to use, instead of the latter, Na2CO3, boil, and neutralize with HNO3. 76. Preliminary Examination for Acids.-The following tests are to be made upon small portions of the dry substance. If the substance is in the form of a solution, a small portion of it is carefully evaporated to dryness and the following test applied: Heat a small portion of the dry substance in a small test- tube with four times its bulk of strong H2SO4 and observe effect. 1° No action ensues. Indication: Silicic, phosphoric, iodic, molybdic, sulfuric, boric (arsenic and chromic found as bases) acids. 70 QUALITATIVE CHEMICAL ANALYSIS. 2° Vapors are evolved: Indication. Violet, coloring starch mucilage blue. . Iodic acid. Reddish, " 11 il orange Bromic acid. Greenish yellow, explosive Chloric acid. Yellow, smell of (CI2O), "euchlorin". . Hypochlorous acid Brownish yellow, irritating Nitrous or nitric. 3° Gases ensue (colorless): Indication. With odor of acetic acid " 11 " rotten eggs " ' ' ' ' burning sulfur Acetic acid. Hydrosulfuric acid. j Sulfurous acid. 1 Thiosulfuric acid. " 11 " peach kernels ( Hydrocyanic acid, t Ferrocyanic acid. ' ' " " burnt sugar Tartaric acid. " irritating odor; white fumes with NH^OH Hydrochloric acid. Fuming, etching glass Oxygen; color changes to brown Odorless; turbid, when shaken lime-water Odorless; burns with blue flame,) Hydrofluoric acid. Chromic acid, with Carbonic acid. = CO +CO2 = Oxalic acid. and renders lime-water turbid ) yj. SYSTEMATIC DETECTION OF THE ACIDS IN SOLUTIONS. As stated in paragraph 75, acids are divided into two great classes, the inorganic and the organic. These are readily distinguished by the action of heat. Salts of inorganic acids when heated to redness are not charred; salts of organic acids (with the exception of acetic, formic, and oxalic) are at once charred, owing to decompo- INORGANIC BASES AND ACIDS. 71 sition and separation of carbon, which fact also applies to all organic substances. The acids do not admit of being grouped as precisely as do the bases; they can, however, be approximately classified by means of appropriate group reagents, thus: Group I. Reagent BaCl2 in presence of HC1. The acids of this group are precipitated by BaCl2, and the precipitate is not dissolved on the addition of HCL Members of the Group: Sulfuric acid and hydrofluosilicic acid. Group II. Reagent BaCl2.-The acids of the second group are precipitated by BaCl2 in neutral solutions only. The precipitate is soluble in HC1. Members of Group II: Phosphoric, boric, oxalic, hydro- fluoric, carbonic, silicic, sulfurous, thiosulfuric, arsenous, arsenic, iodic, and chromic acids. Group III. Reagent AgNO3.-Members of this group are precipitated by AgNO3, but not by BaCl2. Members of Group III: Hydrochloric, hydrobromic, hydri- odic, hypochlorous, hydrocyanic, and hydrosulfuric acids. Group IV. Non-precipitable Acids.-Acetic, chloric, nitric, and perchloric. Acids of this group form with bases soluble compounds and are not precipitated by any reagent. 78. Having located to which group the acid belongs, system- atic confirmatory tests for members of such group are applied, found in the following tables under Indication. 72 QUALITATIVE CHEMICAL ANALYSIS. (A) To a portion of the original add H2SO4 (warm if neces- sary). Result. Indication. Confirmatory Tests to be Applied to Some of the Original Solution. Effervescence with- f out odor. Odor of vinegar. Odor of rotten eggs. Odor of burning sul- 1 fur. 1 Odor of hydro-! cyanic acid. Odor of benzoic acid. Odor of phenol. Carbonate or Bicarbonate. Acetate. Sulfid. Sulfite. Thiosulfate. Cyanid. Ferrocyanid. Ferridcyanid. Benzoate. Carbolate. Phenolsulfonate. Fe2Cl6, red ppt.-MgSO4, white ppt. at once. Fe2Clfi, red ppt-MgSO4, no ppt., but ppt. on boiling. Fe2Cl6, red coloration destroyed by HC1. Alcohol + H 2SO4 + heat = odor acetic ether. Fe2Cl6 + NH4OH = black ppt. HC1 and warm, SO? evolved; no ppt. Add AgNO3, white ppt.; warm it = black ppt. HC1 and warm, SO, evolved and White ppt. of S. Add AgNO3, white ppt.; warm it = black ppt. FeSO4, red ppt. One drop FeSO4 to excess of solution, then Fe2Cl# and HC1 = Prussian blue. FeSO4, light-blue ppt.-Fe2Cl6 = Prussian blue. FeSO4, dark-blue ppt.; Fe2Cl6=no ppt., but coloration. Fe2Cl6, pale-buff color and ppt. Fe2Cl6, violet color; evaporate to dryness, ignite residue, dissolve in HC1, no ppt. with BaCl2. Fe2Cl6, violet color; evaporate to dryness, ignite residue, dissolve in HC1, white ppt. with PaCl2. (B) To a separate portion of the solution add BaCl2. Result. Indication. Confirmatory Tests to be Applied to Some of the Original Solution. White ppt. insol. in HC1. Sulfate. If ppt. is soluble in HQ pass on to next table. Phosphates, oxalates, carbonates, borates, sulfites, thio- sulfates, chromates, silicates, and some other salts are likewise precipitated by BaCl2, but the ppt. so produced is in each case soluble in, or decomposed by, HC1; hence the foregoing test is distinctive of sulfates. INORGANIC BASES AND ACIDS. 73 (C) To a separate portion of the solution (rendered neutral) add CaCl2. Result. Indication. Confirmatory Tests to be Applied to Some of the Original Solution. White ppt. at once in- sol. m HC2H3O2. Oxalate. If ppt. is sol. in HC2H3O2 pass on t© next table. * White ppt. on shak- ing. Tartrate. AgNO3 to neutral solution, 1 drop of NH4OH; boil, mirror is pro- duced. * White ppt. on boil- ing. Citrate. AgNO3 to neutral solution and 1 drop NH4OH, boil; no mirror is produced. * If the precipitate of this group does not answer above, pass on to Table E; likewise remember that the last three tests are applied only where preliminary tests show presence of organic matter. (D) To a separate portion of the solution acidified with HNO3 add AgNO3. Result. Indication. Confirmatory Tests to be Applied to Some of the Original Solution. Yellow ppt. Yellowish-white ppt. White ppt. Orange ppt. lodid. Bromid. Chlorid. Cyanid and Sulfocyanate. Ferrocyanid. Ferri cyanid. Cl water + starch paste= blue color. " " + " " = yellow" Ppt. soluble in NH.OH, insol. iit hno3. Add 1 drop FeSO4 + HC1 + Fe2Cl6 = Prussian blue. Fe2Cl6, red coloration, not destroyed_ + HC1. See Table (A). Fe,Cl8, no ppt., but coloration. 74 QUALITATIVE CHEMICAL ANALYSIS. (E) To a separate portion of the (neutralized) solution add AgNO3. Result. Indication. Confirmatory Tests to be Applied to Some of the Original Solution. Yellow ppt. " Dark-brown ppt. Dark-red ppt. Black ppt. White ppt., turning black on warm- • ing. White ppt., forming mirror when boilec with 1 drop o NH4OH. White ppt., forming mirror when boilec with 1 drop o HC2H3O2. White ppt. f Arsenite, and Phosphate. Arsenate. Chromate, and Dichromate. Sulfid. Sulfite. Thiosulfate. Hypophosphite. Phosphite. Tartrate. Formate. Borate. Metaphosphate. Pyrophosphate. Ppt. sol. in HNOS.-HC1 and H2S =yellow ppt. Ppt. sol. in HNO3.-HC1 and II2S = no ppt. HC1 strong+ H2S gas = yellow ppt. after some little time.-Apply Marsh's test. NH.OH. color not altered.-HC1, color changed to red.-HC1 + H2S, green color is formed. NH4OH, color changed to yellow.- HC1, color not altered.-HC1 + H2S, green color is formed. AgNO3, black ppt., insoluble in dil. acids.-Pb(C2II3O2)s produces black ppt. See Group (A). " " (A). CaCl2, no ppt.-K2Mn2O8, color dis- charged without acid. CaCl2, white ppt.-K?Mn2O8, color discharged with HC1. CaCl2, white ppt. on shaking. Fe,Cl8, red color, destroyed with HC1.-H2SO4 and warm, no odor of acetic acid. Fe2Cl8, faint-yellow ppt.-Evapo- rate to dryness, add H,SO4 and alcohol, ignite = green flame. HC2H3O, and albumin, coagula- tion. HC2H3O2 and albumin, no coagula- tion. INORGANIC BASES AND ACIDS. 75 (F) To a separate portion of the neutralized solution add Fe2Cl6. Result Indication- Confirmatory Tests to be Applied to Some of the Original Solution. Red color, but no precipitate. Violet color, but no I precipitate. Greenish or brown color. Dark-blue precipitate Yellow precipitate. | Black precipitate. Pale-buff ppt. Pink precipitate. Acetate. Formate. Sulfocyanate. Sulfite. Thiosulfate. Pyrogallate. Carbolate. Phenolsulfonate. Salicylate. Ferricyanid. Ferrocyanid. Borate. Oxalate. Sulfid. Gallate. Tannate. Benzoate. Succinate. See in Table (A). " " " (E). " " " (D). " " " (A). " " (A). Milk-of-lime, purple color turning brown.-Solution of gelatin, no ppt. See Table (A). " " (A). H2SO4 and heat, no odor of phenol. See Table (A); " " (A). " " (E). " " (C). " (A). Milk-of-lime, brown color quickly formed.-Sol. of gelatin, no ppt. Milk-of-lime, brown color slowly formed.-Sol, of gelatin, bulky ppt. See Table (A). Strong hot H2SO4, will not char it. (G) To a separate portion of the original solution add a few crystals of FeSO4 (and warm slightly). Result. Indication. Confirmatory Tests to be Applied to Some of the Original Solution. Black color. Nitrite. KI with dil. H2SO4 and starch paste = blue. Black color only after adding strongH2SO6. Nitrate. KI with dil. H2SO4 and starch paste=no blue color. 79- Detection of Acids in Insoluble Substances.-Boil some of the substance in a flask for five minutes or so with a strong solution of Na2CO3, cool, filter, and neutralize the filtrate with HNO3, carefully avoiding excess of the acid. All the acid radicals of the substance will be converted 76 QUALITATIVE CHEMICAL ANALYSIS. into corresponding sodium salts and dissolved in the aqueous solution. Test separate portions of this solution as under 78. SPECIAL TESTS FOR ACIDS OF GROUP I. (Acid Barium Group.) 1. Sulfate.-With BaCl2 gives a white ppt. of BaSO4, insoluble in acids. The solution should be acidified with HC1 before adding the reagent: Na2SO4 +BaCl2 = BaSO4 +2NaCl. 2. Hydrofluosilicate.-With BaCl2 gives an insoluble ppt. of BaSiF6, insoluble in HC1. With KCl gives a gelatinous ppt. of K2SiF6: 2KC1 +H2SiF6 = K2SiF6 +2HC1. 8i. SPECIAL TESTS FOR ACIDS OF GROUP II. (Neutral Barium Group.) 4. Phosphate.-BaCl2 produces a white ppt. of barium phosphate, soluble in HNO3 or HC1: BaCl2 +Na2HPO4 = BaHPO4 +2NaCl. Barium Phosphate. 5. AgNO3 precipitates yellow silver phosphate, soluble in HNO3: 3AgNO3 +Na2HPO4 = Ag3PO4 +2NaNO3 +HN O3. Silver Phosphate. 6. (NH4)2MoO4 (dissolved in HNO3) gives a canary-yellow ppt. of ammonium phosphomolybdate easily soluble in alka- lies. INORGANIC BASES AND ACIDS. 77 7. Magnesia mixture gives a white ppt. of NH4MgPO4. 8. Borate.-Acidulate the solution with HC1, dip a piece of turmeric paper into the mixture and dry it over the gas. The paper acquires a brownish-red color, which is changed to green on moistening it with a drop of KOH. 9. Moisten the dry salt with a little H2SO4, or acidulate the solution, add alcohol, and ignite: a distinct green flame is produced. 10. Oxalate.-Heated with strong H2SO4, carbon monoxid, carbon dioxid, and water are produced. The CO will burn with a blue flame: K2C2O4 +H2SO4=K2SO4 +CO +co2 +h2o. 11. With AgNO% a white ppt. of silver oxalate is produced: K2C2O4 +2AgNO3 = Ag2C2H4 +2KNO3. Silver Oxalate. 12. With CaCl2 a white ppt. of calcium oxalate is produced «ven with dilute solutions. The ppt. is soluble in HC1. CaCl2 +K2C2O4=CaC2O4 +2KC1. w Calcium Oxalate. 13. Carbonate.-Treated with dilute acid, violent effer- vescence takes place, carbonic anhydrid being evolved, which produces turbidity in a drop of Ba(OH)2 solution held on a glass rod near the mouth of the test-tube: Na2CO3 +2HCl = 2NaCl +H2O +CO2. 14. Sulfite.-Heated with a small piece of zinc and a few drops of H2SO4, H2S will be evolved, which blackens lead acetate paper. 15. With AgNO3 sulfites produce a white ppt. which on being heated darkens and deposits metallic silver. 78 QUALITATIVE CHEMICAL ANALYSIS. 16. Thiosulfates.-With BaCl2 produce a white ppt. of BaS2O3. 17. With Pb(C2H3O2)2 a white ppt. of lead thiosulfate is formed: Na2S2O3 +Pb(C2H3O2)2 = PbS2O3 +2NaC2H3O2. 18. IIC1 added to a solution of a thiosulphate produces a slowly forming ppt. of S and an evolution of SO2. 19. Arsenites.-With AgNO3 produce a yellow ppt. of Ag3AsO3 (silver arsenite) soluble in NH4OH. A few drops of NH4OH facilitate the reaction. 20. Arsenates.-With AgNO3 produce a light-brown ppt. of AgAsO4 (silver arsenate). 21. MgSO4+NH4C1+ (NH4)H0 produce a white ppt. of MgNH4AsO4 (distinction from arsenites). 22. Iodates.-With AgNO3 produce a white crystalline ppt. soluble in NH40H: 2KIO3 +2AgNO3 = 2AgIO3 +2KNO3. Silver Iodate. 23. On heating, iodates are decomposed, oxygen evolved, and iodine given off in violet fumes. 24. Chromates.-With BaCl2 form a yellow ppt. of barium chromate. 25. With AgNO3 chromates give a red ppt. of silver chromate soluble in HN03: 2AgNQ3 +K2CrO4 = Ag2CrO4 +2KNO3. Silver Chromate. 26. Silicates.-With BaCl2 produce a white precipitate of BaSiO3, which is decomposed on addition of HC1, Si(0H)4 separating as a gelatinous ppt. INORGANIC BASES AND ACIDS. 79 27. With HC1 silicates are thrown out of solution as Si(OH)2 = a gelatinous ppt. 82. SPECIAL TESTS FOR ACIDS OF GROUP III. 28. Chlorids.-Heated with H2SO4 and MnO2 yield chlorin gas, recognized by its greenish color, odor, and its bleaching action on litmus and indigo. 29. With AgNO3 a curdy white ppt. is obtained, sol. in NH4OH, insol. in HNO3. 30. Hypochlorites.-Heated with dilute II2SO4 give off chlorin, recognized by its odor; a few drops of solution KI added and starch paste = a blue color of starch iodid. 31. Indigo and litmus solutions acidified with dilute H2SO4 are decolorized. 32. Nitric acid evolves hypochlorous acid-HC1O-from hypochlorites. 33. Nitrites.-A solution of a nitrite mixed with an equal volume of a freshly prepared solution of FeSO4 is floated upon some concentrated HC2H3O2 in a test-tube: a dark brown ring forms at line of contact. This test distinguishes nitrites from nitrates, the latter requiring H2SO4 to produce the brown ring. 34. The nitrite solution acidulated with dil. H2SO4 and some KI and starch solution added = a blue color. 35. Sulfids.-With AgNO3 produce a black ppt. of Ag2S. 36. With strong HC1 and heat sulfids are decomposed and H2S evolved, recognized by its odor; also, if a piece of paper moistened with Pb(C2H3O2)2 is held over the mouth of the test-tube, a dark coloration (PbS) results. 37. With NaOH and some sodium nitro-ferricyanid a pur- plish-reel color is produced. 38. Bromids.-With AgNO3 produce a pale-yellow ppt. of AgBr, insoluble in dilute HN03, but readily soluble in Na2S2O3: KBr +AgNO3 = AgBr +KN03. 80 QUALITATIVE CHEMICAL ANALYSIS. 39. With chlorin water the solution is colored through the liberation of bromin; add a few drops of chloroform to the solution and shake; the chloroform will carry to the bottom the dissolved Br as a golden-yellow solution: KBr+Cl=KCl+Br. 40. Liberate Br as in preceding test and add starch paste; the orange coloration is due to the formation of starch bromid. 41. Bromates.-With dilute H2SO3 liberate Br; add starch paste and orange-colored starch bromid will form: 2KBrO3 +5H2SO3 = 3H2SO4 +2KHSO4 +H2O +Br. 42. lodids.-With solutions of CuSO4 acidified with H2SO4 produce a dirty-white ppt. of CU2I2 (distinction from bromids and chlorids). 43. Liberate I as in test 39, or by the addition of strong H2SO4, add chloroform, and shake: it will dissolve in the chloro- form and be carried to the bottom as a purple-colored solution. 44. Liberate iodin as in 39, add starch paste = characteristic blue color of starch iodid. 45. Cyanids.-Prepare a mixture of solutions of FeSO4 and Fe2C16, add NaOH and a few drops of HC1, then a solution of a cyanid: a blue ppt. Prussian blue will develop. (1) 2KCy+FeSO4 = Fe(Cy)2+K2SO4. (2) 4KCy+Fe(Cy)2 = K4FeCy6. (3) 3K4FeCy6 +2Fe2Cl6=Fe4(FeCy6)3 +12KC1. 46. Heated with a few drops of dil. H2SO4, cyanids decom- pose, evolving HCy, recognized by the odor of bitter almonds: 2KCy+H2SO4 = K2SO4 +2HCy. {Caution! The gas so evolved should be cautiously sniffed, it being highly poisonous.) INORGANIC BASES AND ACIDS. 81 47. Cyanates.-With HC1 in presence of H20 form cyanic acid and corresponding Cl salts; heating this splits the acid and the chlorid into NH4CI+CO2, for both of which test with appropriate reagents. 48. Chlorate, Bromate, and Iodate.-These salts, in the dry state, when heated evolve oxygen and are reduced to chlorid, bromid, and iodicl respectively. Hence if the salt deflagrates when heated with charcoal, heat another portion on porcelain and test portions of the residue for chlorids, bromids, and iodids with appropriate reagents. 49. Chlorids, Bromids, and Iodids.-In mixtures these are separated and identified as follows: Place a small quantity of the mixture in a test-tube, add a few grains MnO2 (free from chlorids) and a drop of dilute H2SO4, and boil. If violet vapors are evolved=iodid. Add 2 more drops of the acid and boil again until all the I is volatilized. Now add about 30 drops more of H2SO4 and boil. If brown vapors are given off = bromid. Boil until all the Br is volatilized, then allow to ■cool. To the residue add an equal bulk of concentrated H2SOt and warm. If a green gas is evolved (with an odor of Cl) = chlorid. Apply the bleaching test as in 28. 83. SPECIAL TESTS FOR ACIDS OF GROUP IV. 50. Nitrates.-Upon being heated evolve oxygen; if acidified with H2SO4 and heated they are decomposed into NO2 and H2O with the evolution of oxygen. 51. When heated on charcoal they deflagrate violently. 52. A solution of a nitrate mixed with an equal volume of freshly prepared FeSO4 sol. and floated on H2SO4 = a brown ring at line of contact. 53. Chlorates.-When heated are decomposed into chlorids as described in 48 and are similarly tested for. 54. Strong HC1 decomposes chlorates with evolution of Cl and C12O4 mixture, known as "euchlor" or euchlorin. 82 QUALITATIVE CHEMICAL ANALYSIS. 55. Perchlorates.-In the dry state evolve oxygen on being heated. 56. Sulfocyanates.-Heated with dilute H2SO4 give off HCy (see Caution in 46) and a ppt. of S forms. 57. With CUSO4 sulfocyanates produce a black crystalline ppt., which changes to white on the addition of FeSO4. 58. With Fe2C16 a blood-red solution is produced. 59. Ferrocyanids.-With CuSO4 produce a brownish-red ppt., Cu2FeCy6: K4FeCy6 +2CuSO4 = Cu2FeCy6 +2K2S04. 60. With AgNO3 a white ppt. of Ag4FeCy6 is formed: I\4FeCy6 +4AgNO3 = Ag4FeCyo +4KNO3. 61. With Fe2Clo = a deep-blue ppt. 62. Ferricyanids.-With AgNO3 produce an orange-colored ppt. of Ag6 (FeCy6)12, insoluble in HNO3, but soluble in KCy: K6(FeCy) i2+6AgNO3 = Age(FeCy)i2 +6KNO3. 63. With FeSO4 = a blue ppt. 64. Hypophosphites.-When the dry salt is heated in a test- tube, PH3 is given off, which bursts into flame. 65. With AgNO3 a white ppt. forms which quickly turns brown. 66. In acidulated solutions IIgCl2 gives white ppt., which on heating turns black. 67. Carbonates and Bicarbonates.-Both effervesce when H2SO4 is added, giving off a colorless gas. 68. HgCl2 produces a red , ppt. = carbonate; HgCl2 produces a white ppt. = bicarbonate. INORGANIC BASES AND ACIDS. 83 84. SPECIAL TESTS FOR ORGANIC ACIDS. 69. Acetates.-Heated with strong H2SO4 give off acetic acid, recognized by its strong odor of vinegar: NaC2H3O2 +H2SO4 = NaHSO4 +CH3COOII 70. Heated with alcohol in oresence of strong H2SO4 acetic ether is evolved: NaC2H3O2 +C2H5OH+H2SO4 = CH3COOC2H5+NaHSO4 + H2O. 71. With Fe2Cl6 = a red-colored solution of Fe2(C2H3O2)6, to which add HC1: the red color is discharged (distinction from sulfocyanids). 72. Citrates.-Heated in a test-tube char slowly, emitting a weak odor of burnt sugar: 2K3C6H5O7 = 3K2CO3 +5H2O +C9. 73. With CaCl2 citrates yield, on boiling, a white ppt. of Ca3(C6H5O7)2: 2K3CeH5O7 +3CaCl2=Ca3(C6H5O7)2 +6KC1. 74. Tartrates.-Heated in a dry test-tube char rapidly (difference from citrates), evolving CO (test as in 10) and a strong odor of burnt sugar: K2C4H406 = K2CO3 +C2 +CO +2H2O. 75. With CaCl2 a white precipitate, CaC4H4Oc, forms on shaking, without heating (distinction from citrates). Wash the above ppt. with H2O, and add KOH: it dissolves (distinction from citrates). 84 QUALITATIVE CHEMICAL ANALYSIS. 76. The solution warmed with AgNO3 and a few drops of NH4OH==a silver mirror. 77. Benzoates.-With HC1 a flocculent ppt. of benzoic acid forms: NH4C7H5O2 +HC1 = HC7H5O2 +NH4C1 (distinction from succinate, the latter not ppt'g with HC1). 78. Heat some dry salt with twice its weight of Ca(OH)2: benzene is evolved: (1) 2NH4C7H5O2 +Ca(OH)2 =Ca(C7H5O2)2 +2NH3 +2H2O. (2) Ca(C7H5O2)2 +H2O = 2CgH6 +CaCO3 +CO2. Benzene. 79. With Fe2Cle=a light buff-colored ppt. 80. Salicylates.-Heated in a dry test-tube decompose into phenol, CO2, and carbonate: 2NaC7H5O3 +H2O = Na2CO3 +2C6H5OH +CO2. Phenol. 81. With Fe2Cl6 = a violet-colored ppt. of ferric salicylate,. Fe2(C7H5O3)e: 6NaC7H5O3 +Fe2C16=Fe2(C7H5O3)6 +6NaCl. 82. Formates-Heated in the dry state with strong H2S04 does not char, but evolves CO and H2O. (Test for CO by 9.) NaCHO2 +H2SO4=NaHSO4 +CO +H2O. The fact that it does not char distinguishes it from all other organic acids commonly met with, except oxalic acid. 83. With Fe2Cl6 = a red coloration, discharged by HC1 (distinction from sulfocyanids). 85 INORGANIC BASES AND ACIDS. 84. With AgNO3 in presence of HC2H3O2, on boiling, for- mates deposit a silver mirror on the side of the tube (distinction from acetate): (1) NaCHO2+AgNO3 = AgCHO2+NaNO3. (2) 2AgCHO2 = Ag2 +H2O +CO +CO2. 85. Lactates.-Heated with excess of strong H2SO4 give off a large quantity of CO. (There are no characteristic tests for lactates.) Heated with dilute H2SO4 lactates yield acetal- dehyd and formic acid: CH3 CH. OH = CH3 H I I + I COOH COH COOH 86. Molybdates.-Heated with water in presence of alcohol and a drop of H2SO4, blue color is produced. 87. Heated with solutions of Na2HPO4 and NaOH in pres- ence of HNO3, a canary-yellow ppt. of molybdenum-ammonium phosphate falls. 88. Tannates, or Tannin.-With Fe2Cle = a blue-black ppt. of ferric tannate (ink). 89. Gallates, or Gallol.-With Fe2C16=a blue-black ppt. soluble in excess to a green solution (distinction from tannates). 90. Pyrogallates, or Pyrogallol.-With Fe2Cle = a red color- ation discharged by HC1. 91. Valerates.-Heated in a dry test-tube evolve valeric acid, leaving a residue of a carbonate. 92. Meconates.-With a neutral Fe2Cl6, solutions of a meconate give a red solution of iron meconate, Fe2(C7H4O7)2. Divide the solution into two parts, a and b. To (a) add HgCl2: the color remains. To (6) ' ' HC1: the color is not discharged. (This reaction is used in testing for opium or its preparations.) 86 QUALITATIVE CHEMICAL ANALYSIS. Acetates and sulphocyanates give the same red color, bw that produced by acetates is discharged by both HC1 anc HgCl2, while the color produced by sulphocyanates with Fe2Cl< is discharged by HgCl2 only. 93. Phenolates, also called Carbolates.-When treated with Fe2C16 give a reddish-violet color similar to that produced with salicylates. Heated with strong H2SO4, an odor of phenol is evolved: NaC6H5O +H2SO4 = NaHSO4 +C6H5OH. (Distinction from salicylates.) PART III. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 85. If a substance chars when heated on platinum foil, or burns with evolution of carbon dioxid, its organic nature is established. The Procedure for the Detection of the Ultimate Constituents of Organic Substances is as follows: (1) Carbon and Hydrogen.-Mix a small quantity of the substance with about six times .its bulk of freshly ignited and powdered cupric oxid, place the mixture in a small test-tube and cover it with a layer of cupric oxid. Then close the tube securely with a cork bearing a delivery-tube bent twice at right angles, and apply heat, (a) Gas is evolved (CO2). The gas is passed into a clear solution of Ba(OH)2. If the solution becomes turbid (through formation of BaCO3), carbon is indi- cated. (&) If drops of water or moisture are deposited in the upper, cold part of the tube, hydrogen is indicated. (2) Nitrogen.-If a substance, when heated on platinum emits an odor of burnt hair or horn, nitrogen is indicated. The presence of nitrogen is, however, more accurately determined as follows: Mix about 2 gm. of the substance with 4 gm. of dried powdered soda-lime, and heat. If nitrogen is present, there will be observed an odor of NH3, recognized also by its turning red litmus blue, and by its forming white fumes when a glass rod moistened with HC1 is brought near the mouth of the tube. (3) Chlorin.-The presence of the halogens in most organic 87 88 QUALITATIVE CHEMICAL ANALYSIS. compounds cannot be detected by the simple addition of silver nitrate; therefore a method similar to the following must be employed: Mix 1 gm. of the substance with 2 gm. of pure CaO in a test-tube and heat to redness. Then dissolve the residue in distilled water strongly acidulated with HNO3, filter, and test for chlorin with AgNOs. In this process the CaO is converted into CaCl2. (4) Sulfur.-(In Solids.) Mix 1 gm. of the substance with 1 gm. each of KNO3 and KOH and subject the mixture to fusion. The sulfur is oxidized, and converted into K2SO4. The fused mass is then dissolved in distilled water, acidified with HC1, and Rested with BaCl2. A white ppt. (BaSO4) indi- cates sulfur. (In Liquids.) Sulfur is detected by heating 3 cc. of the liquid with strong HNO3. This converts the sulfur into II2SO4, which, after diluting with water, is tested with BaCl2. (5) Phosphorus may be detected as described above (for sulfur in solids). The fusion converts phosphorus into H3PO4. The fused mass is dissolved in water and tested for phosphate with magnesia mixture. Another way is to heat about 2 gm. of the substance with HNO3, dilute with water, filter, and test separate portions of the filtrate with, first, Fe2Cle in presence of sodium acetate = a brown ppt.; and, second, ammonium molybdate solution = a yellow ppt. 86. BEHAVIOR OF ORGANIC SUBSTANCES WITH IMMISCIBLE SOLVENTS. Upon agitating the substance with distilled water acidulated with 2% of H2SO4, and adding half its volume of an immiscible solvent (ether, chloroform, or benzene) the following are extracted: (1) In the Acidulated Aqueous Liquid there may be dissolved carbohydrates, soluble alkaloidal salts, acids, organic bases, and QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 89 proteids. Add a small excess of NaOH solution and half its volume of an immiscible solvent and again shake, thus further separating the above into (a) and (b). (a) The Alkaline Aqueous extract may contain: Carbohydrates; as, dextrin, sugars, gums. Soluble Alcohols; as, methyl, ethyl, propenyl. Soluble Acids; as, acetic, tartaric, citric, lactic, malic, oxalic. Alkaloids and Organic Bases; as, urea, curarine, cinchonine, pyridine, and morphine. Coloring matters; as, indigo, cochineal, cudbear. Proteids; as, albumin, casein, gelatin. (b) The Immiscible layer may contain: Vegetable Alkaloids; as, quinine, strychnine, aconitine, atropine, nicotine. Coal-tar Bases; as, aniline, chrysotoluidine, pyridine, and their homologues. (2) In the Immiscible Solvent there may be dissolved hydro- carbons, oils, acids, coloring matters, resins, phenols, and glucoids. Add water containing a small excess of NaOH and shake again, thus further separating the above into (a) and (b). (a) The Alkaline Aqueous Extract may contain: Fatty acids; as, stearic, oleic, palmitic, valeric. Aromatic acids; as, benzoic, salicylic, phthalic. Acid coloring matters and dyes; as, picric or chrysophanic acid; aurin, saffranin, alizarin, or bilirubin. Acid Resins; as, colophony (common pitches). Phenols; as, phenic and cresylic acids; thymol and creosote. Glucosids; as, santonin, picrotoxin. (b) The Immiscible layer may contain: Hydrocarbons, solid; as, paraffin, napthhalene, an- thracene. 90 QUALITATIVE CHEMICAL ANALYSIS. Hydrocarbons, liquid; as, petroleum products, rosin- oil, benzene. Essential oils; as, turpentine, terpene, and oxygenated oils. Nitro-compounds; as, nitro-benzene. Chloroform, also Ethers; as, ethyl oxid, ethyl acetate, etc.; nitro-glycerin. Fixed fats, oils, and waxes. Neutral resins and coloring matters. Camphors; as, laurel-camphor, borneol, menthol. Insoluble Alcohols; as, amyl, cetyl, and cholesterin. Glucosids; as, saponin, santonin, and digitalin. Weak Alkaloids; as, caffeine, narcotine, piperine, col- chicine. 87. BEHAVIOR OF ORGANIC SUBSTANCES WITH FEHLING'S - SOLUTION. The substance should be made perfectly neutral and brought into solution. One cc. of the solution is heated with 10 cc. of Fehling's Reagent to boiling. In some cases the reduction occurs in the cold or on gently heating the liquid. A yellow or orange-red precipitate or turbidity caused by the precipita- tion of cuprous oxid (CU2O) indicates reducing substance, thus: Fehling's Reagent is Reduced by Fehling's Reagent is Not Affected by Carbohydrates. - Lactose, dextrose, Carbohydrates.-Mannite, saccharose, Levulose, maltose, mannitose, ara- dulcite, cellulose, dextrin, arabin. binose, galactose. Alcohols and Phenols.-Alcohol, gly- Alcohols and Phenols.-Aldehyd, cerin, phenol, benzoic and salicylic chloral, chloroform, valeric aldehyd, aldehyds. resorcinol. Organic Acids.-Acetic, oxalic, suc- Organic Acids.-Pyrogallic, gallotan- cinic, lactic, tartaric, citric, gallic, nic, trichloracetic. mucic, benzoic, and salicylic. Inorganic Acids.-Arsenous. Inorganic Acids.-Sulfurous, etc. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 91 88. A SYSTEMATIC SCHEME FOR THE IDENTIFICATION OF THE MOST IMPORTANT CARBOHYDRATES* Step 1.-General reaction. J To 5 cc. of a weak solution of the substance add a few drops of 15 per cent alcoholic solution of alphanaphthol, and overlay this on strong sulphuric acid; a violet or blue zone at the line of Contact indicates a carbohydrate. If the substance is insoluble in water, dissolve in 25-per cent, sulfuric acid and float over this solution a mixture of water and alphanaphthol, and observe as above. Step 2.-Shake about 1 grm. of the substance with 10 cc. of water in a test-tube. Decant or filter from any insoluble residue, which may be starch or cellulose. Save the filtrate for the succeeding steps, and test the residue as follows: To the insoluble matter in the test-tube (not on the filter- paper) add a few drops of a dilute aqueous solution of iodin; a blue color indicates starch. Step 3.-Take a portion of the filtrate obtained in step 2 and divide into two parts. To one part add an equal volume of strong alcohol; sc precipitate indicates dextrin. To the other part on a white slab add a few drops of dilute solution of iodin; a blue color indicates cooked starch, and a reddish-brown color, dextrin. * E. H. Bartley's Clinical Chemistry, p. 17. 92 QUALITATIVE CHEMICAL ANALYSIS. 89. CHART FOR THE DETECTION OF THE MORE COMMON ORGANIC COMPOUNDS OF PHARMACEUTICAL INTEREST. Dissolve a small quantity of the dry substance in a little dilute HC1, and add a drop or two of potassio-bismuthic iodid solution. If a reddish-brown ppt. forms, an alkaloid is indicated. Apply Step I. If no ppt. forms, pass on to Step V and then to Step VI. Step I.-To drop of HNO3 on a white porcelain tile add a small quantity of the substance and observe the color. Red changing to yellow = Morphine. Red = Brucine. Frohde's Reagent gives a purple color. Sulphuric acid containing a crystal of KIO3 = a dark brown. A few drops of Fe2Cl6 sol. added to a neutral solution (1:100) of mor- phine = a blue color destroyed by acids. Sulphuric acid containing in each cc. 1 drop of sol. of formaldehyde gives with morphine an intense purple color. Color changes to purple on addition of a drop of Na2S2O3 solution. To crystal of the alkaloid add chlorin-water = an evanescent rose- red. To another crystal add HNO,, then some solution of AgNO3, and warm = a carmine-red. To another crystal add bromin- water = a yellow ppt. and forming a red sol. on warming. Yellow changing to Redon heating = Physostigmine. With H2SO4 Physostigmine yields a faint yellow color. With H2SO4 containing a crystal of KI03 = a purple color changing to yellowish red. KOH added to the aqueous sol. yields a white ppt. which quickly turns pink soluble in excess to a pink or red sol. Reddish Brown = Aconitine. With H2SO4 containing a crystal of ammonium vanadate = orange color. With H2SO4 and a grain or two of sugar = red color. With H2SO4 on gently warming = violet color. With Frohde's Reagent = a yellow- brown color. Red Crystals with yellow-colored solu- tion = Codeine. With H2SO4 and warming = a violet color. With H2SO4 and a trace of FeCl6 = a violet-blue color. With H2SO4 containing a little HNO3 upon heating gives a blood- red color. Purple fading to orange = Apomorphine. I With H2SO4 and a trace of Fe2Cl6 = a pale blue. With H2SO4 containing a trace of HNO3 = a blood-red color. With H2SO4 containing a little paraldehyde = a green color fading to reddish brown. Dilute Fe2Cl6 sol. colors the alkaloid solution red. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 93 Step II.-Cover a few grains of the alkaloid with a drop or two of cone. H2SO4 on a white porcelain tile, and add a small fragment of potassium dichromate. Observe effect. Deep Blue Green quickly changing to violet, purple, cherry-red and finally to orange = Strychnine. With H2SO4 containing a trace of am- monium vanadate = a violet-blue, gradually changing to cherry-red. With H2SO4 containing a trace of KIO3 = a violet color, changing to purple. (See also Acetanilide.) color slowly formed = Caffeine. If a small quantity of salt be dis- solved in 1 cc. of HC1 and a little KC103, and the sol. evapo- rated to dryness, the residue, sub- jected to the vapor of ammonia, will acquire a rich purple color. (See also Cinchonidine.) Odor of bitter almonds = Atropine. Heated with a few cc. of H2SO4 = a peculiar odor, resembling a mix- ture of rose, orange flower and melilot. The addition of a crystal of K2Cr2O7 develops an odor of bitter almonds. With AuCl a yellow lusterless ppt. is produced in a HC1 solution of atropine. Pale Yellowish Pink = Cocaine. If 5 drops of CrO3 sol. (1:20) be added to 5 cc. of cocaine sol. = a yellow ppt., dissolved on shaking. On now adding 1 cc. of HC1 an orange-colored ppt. is produced. Its solution in HC1 gives with K2CrO4 sol. an orange ppt. With KMnO4 sol. a violet ppt. is produced. Step III.-To a fragment of the alkaloid on a porcelain crucible cover add a few drops of cone. HC1 and warm. A Rose-red color = Veratrine. Confirmatory tests: Heated with H2SO4 = a cherry-red color. With H2SO4 and sugar = a green changing to blue. With HN0s = a yellow color. With Frbhde's reagent=a cherry-red. (See also Physostigmine.) 94 QUALITATIVE CHEMICAL ANALYSIS. Step IV.-Heat a little of the original in a dry test-tube. Vapors are evolved, first yellow then red = cinchona alkaloids, Take another small portion of the alkaloid, dissolve it in water with the aid of the least quantity of dilute H2SO4, then add some bromine-water, and a slight excess of ammonia-water. An Emerald Green Color indicates Quinine or Quinidine; a white ppt. may indicate Cinchonine or Cinchonidin. Apply the following tests: Reagent. Quinine. Quinidine. A 1% solution of the alka- loid, made by using the smallest possible quantity of dil. H2SO4 and neu- tralized with NH4OH, is treated with one drop of H2O2 and one drop of CuSO4 sol. and boiled. Intense red color changing to blue and green. Intense red color changing to blue and green. Dissolve a small quantity of the alkaloid in a mixture of acetic acid and alcohol with a few drops of H2SO4, boil, and add tr. iodin slowly. Bronze or olive-green crystals separate on cooling. (Quinine- iodosul- phate.) No ppt. or crystals. To a neutral aqueous solu- tion add (NH4)2C2O4 or KNaC4H4O6 sol. White ppt. Precipitate only on addition of KI and shaking. Frohde's Reagent. Green color. Green color. Reagent. Cinchonin. Cinchonidin. Make a nearly neutral solu- tion of the alkaloid. Add some sat. sol. of KNaC4H4O8. No white ppt. unless excess of NH4OH is added. A white ppt. Make a solution of the alkaloid in HC2H3O2. Add some NH4OH, and then an excess of ether. The ppt. does not dissolve in the ether. The ppt. dissolves in the ether. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 95 Step V.-If the substance is not an alkaloid, place a small portion of it on a porcelain crucible cover, add a drop or two of Frohde's Reagent and observe the color changes. Salicin. Santonin. Intense violet color changing to reddish brown. With H2SO4 = a bright-red color which disappears on the addition of water. To some of the substance add dilute sulfuric acid and a crystal of K2Cr2O7 and boil = odor of sweet clover (salicylic aldehyd). On heating a portion of the sub- stance in a test-tube until it turns brown, then adding water and a drop of Fe2Cla sol. = a violet color. Slate-blue color on warming. Add a drop of Fe2Cl6 to some H2SO4, warm, and add some of the sub- stance = a violet-red color chang- ing to brown. On heating a portion of the sub- stance with alcoholic KOH sol. = a red color. The substance is soluble in NaOH, reprecipitated by acids. Elaterin. Aloin.- Faint red changing to olive-green on warming. Add a drop of phenol, then a drop of H2SO4, to some of the substance, and warm = a rose-red color. With H2SO4 = a yellow color changing to red. With H2SO4 + a drop of formaldehyde = a brown color. With H2SO4 + a trace of ammonium vanadate = a blue, changing to green and brown. Yellow color changing to green. Ammonia-water and alkali sols, dis- solve aloin forming a yellow sol. quickly turning red. With cone. H2SO4+a crystal of K2Cr2O7 = an olive-green, and finally, on standing, a blue color. With bromine-water = a pink color. With AuC13 in an aqueous solution = a carmine-red changing to violet. With a drop of Fe2Clf, sol. its alco- holic sol. gives a brownish-green color. HNO3 gives with barbaloin a crimson, with nataloin a red, and with socaloin a brown, ppt. Step VI.-Heat some of the substance in a dry test-tube and observe odor or other effect. (a) Odor of Phenol indicates: Phenol (see 162). Phenolates (par. 78, Tables A and F), or Phenolsulphonates (par. 78, Tables A and F). 96 QUALITATIVE CHEMICAL ANALYSIS. (b) Odor is Pungent; may be Chloral, Benzoic Acid, Ben- zoates, or Butyl Chloral. Chloral. Benzoic Acid or Benzoates. Butyl Chloral. Heated with KOH or NH4OH an odor of chloroform is evolved and a formate of the base is produced. Warmed with a few drops of aniline and some KOH = a very disagree- able odor of phenyl- isocyanide. Warmed with a few drops of NH4OH and a little AgN03 sol. = a silver mir- ror. Boiled with Fehling's sol. = a red ppt. Upon heating benzoic acid with freshly slaked lime in a dry test-tube ben- zene (benzol) is evolved. A sol. of benzoic acid in NaOH neutralized care- fully gives with neutral ferric chloride sol. a pale buff or flesh-colored ppt. See par. 78, Tables A and F, also par. 84, No. 77, for tests for benzoates. Sparingly soluble in water. Boil with NaOH, neutralize with dilute HC2H3O2 and add AgNO3 sol. = a white ppt. (c) Odor is Pungent; with lodin Fumes indicates Iodoform, Iodol, or Aristol. Iodoform. Icdol. Aristol. A yellow insol. powder. When boiled with NaOH and the sol. neutralized with HNO3 = a yellow ppt. on adding AgNO3 sol., and a blue color on adding starch sol. A grayish-brown pow- der very sparingly soluble in water. When dissolved in cone. H2SO4 a green sol. results gradually changing to brown. A bright chocolate-colored powder, with an aro- matic odor. It is not sol. in alkaline hydroxid solutions. Heated with cone. H2SO. it decomposes, ana iodine separates. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 97 (d) Odor is Camphoraceous; may be Camphor, Thymol, or Menthol. Camphor. Thymol. Menthol. Soluble in the volatile solvents, and in fixed oils. Its alcoholic solution poured into cold water = a curdy white ppt. When triturated with hydrated chloral lique- faction ensues. It is inflammable and burns with a lumin- ous, smoky flame. An aromatic thyme- like odor. Soluble in ether, chlo- roform, alcohol, and oils, also in glacial acetic acid. Its sol. in the latter when treated with H2SO4 and a drop of HNO3 exhibits a bluish-green color by reflected light. If heated with NaOH sol. in a test-tube a pale-red sol. is formed which becomes darker on standing. A few drops of chloroform added gives a violet color. Soluble in alcohol, chlo- roform and ether. It has a peppermint-like odor. It is soluble in glacial acetic acid, but does not respond to the test for thymol. Heated with diluted sul- furic acid 1: 2 = a deep- blue color. (e) Odor is Acrylic (Fatty Acid); indicates Soap, Oleates, or Stearates. Soap.-Dissolve in water, add HC1 and shake, add some ether and again shake; then let the mixture stand so that the ethereal layer can separate; remove the upper layer and evaporate: the residue if liquid is oleic, and if solid, stearic acid. The HC1 sol. is evaporated to dryness and tested for K and for Na. Oleates and Stearates of the heavy metals are treated in the same way. The acid sol. residue being tested for the metals commonly combined with these fatty acids, i.e., Zn, Pb, Hg, etc. (/) Odor resembling Burnt Bones; may indicate Oxgall. To a warm aqueous solution of oxgall add a crystal of sugar; shake, and add H2SO4 cautiously until the ppt. first formed is redissolved; a brownish- red color gradually develops, changing to carmine, purple, and violet. 98 QUALITATIVE CHEMICAL ANALYSIS. (g) Odor of Burning Sugar; may be Sugars, Dextrin, Starches, Gums, Tartaric Acid or Tartrates. Apply special tests. For tartrates, see par. 84, No. 74. For the sugars, see the Table below; also see Scheme in par. 88 for other carbohydrates. Cane-sugar. Milk-sugar. Strong H2SO4 chars it immediately. Does not reduce Fehling's sol. Mixed dry with KC103 crystals and a drop of cone. H2SO4 added, it defla- grates. It does not ferment with yeast until left in contact for some time. Boiled with NaOH = no effect. It does not form a compound with phenylhydrazine. Strong H2SO4 chars it slowly. It reduces Fehling's sol. It does not ferment with yeast. It combines with phenylhydrazine to form phenyl-lactosazone in acetic acid solutions. Boiled with NaOH = no effect. Graps-sugar. Dextrin. Strong H2SO4 does not char it until heated. It readily reduces Fehling's sol. It also reduces alkaline solutions of Bi, Ag, and Hg. In a solution acidified by HC2H3O2 it forms, with excess of phenyl- hydrazine, a yellow ppt. of phenyl- dextrosazone. It ferments readily upon adding yeast to its solution. Boiled with NaOH=a deep-brown color. Strong H2SO4 = no effect. In aqueous sol. reduces Fehling's sol. only after long boiling. Boiled with NaOH=no effect. Starches. Insoluble in cold water, but on boiling it forms a mucilage, which gives a blue color with iodin. Boiled with dilute sulfuric acid, it is converted into dextrose, and then reduces Fehling's sol. Gums. Soluble in cold water, from which sol. it is precipitated by alcohol, borax or lead-acetate solution. Gum arabic is an arabate of calcium. Ignite some of it, dissolve the ash in dilute acetic acid and test for Ca, with (NH4)2C204. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 99 (h) If detonation occurs, it indicates Picric Acid. Dissolve a little of the substance in NaOH sol., add a little sugar, and warm the mixture = a blood-red color. To an aqueous solution add a solution of gelatin = a white ppt. Its aqueous sol. precipitates albumin, and gives a green ppt. with ammonio-copper sulfate. (1) If it burns with a smoky flame, it may be resin. Resin. Insoluble colored substance. A small piece of it treated with strong H2SO4 gives a red coloration; add a drop of H2O to this = balsamic, turpentiny odor. • Guaiacum Resin. Insoluble colored substance. Dis- solved in alcohol and treated with Fe2Cl6, gives a blue coloration. A small piece of it treated with strong H2SO4 for a few seconds, then water added, gives a characteristic balsamic odor. (/) If it at first melts and then upon highly heating burns away entirely, it may be acetanilide, antipyrine, phen- acetin, saccharin, naphthalene, or urethane. Acetanilide: 1 grm. of acetanilde heated with 5 cc. of cone. sol. of KOH, and 1 cc. of chloroform added = a disagreeable odor of phenyl isocyanide (dist. from antipyrine and exalgine). 0.1 grm. boiled with 2 cc. HC1 and 3 cc. of phenol sol. (1: 20) and then mixed with 5 cc. of a clear sol. of chlorinated lime = a brownish-red color, becoming blue upon supersaturating with NH40H. 1 grm. heated with 10 cc. of water, the sol. cooled and filtered and treated with bromin-water drop by drop gives a whitish ppt. of parabromoacetanilide. Antipyrine, Phenazonum, Phenyldzmethylisopyrazolon.- If .1 grm. of NaN02 and 12 cc. of 1% sol. of anti- pyrine be mixed and 1 cc. of dil. H2SO4 added, a deep-green color (iso-nitrosoantipyrine) develops. A sol. of antipyrine (1:1000) treated with 1 drop of Fe2Cle 100 QUALITATIVE CHEMICAL ANALYSIS. sol. = a deep-red color, which is turned yellow by H2SO4. Tannic acid sol. gives a white ppt. HNO3 produces a red coloration. Phenacetin, Acetphenetidin.-HNO3 produces a yellow color which persists on heating. Boiled with cone. HC1, the solution diluted with water, cooled and filtered, and then 3 drops of sol. of &O3 (1:30) added, a ruby-red color is produced. Fe2Cle sol. produces a yellow solution, which becomes blood-red on boiling. Saccharin, Glusidum, Benzosulfinid.-It has an intensely sweet taste. It is soluble in alkali solutions and in NaHCOs sol. with evolution of CO2. If subjected to a high temperature it melts and finally burns, giving off an odor of essential oil of bitter almonds. Heated to redness with Na2CO3 it chars and gives off an odor of benzene. Its solution in NaHCOs, neutralized with HC1, gives with Fe2C16 a reddish-brown color. Naphthalene.-It melts and volatilizes; its vapor is inflammable, burning with a luminous smoky flame. It may be recognized by its characteristic odor, resem- bling that of coal-tar. It is insol. in water but sol. in the volatile solvents. Urethane, Ethyl Carbamate.-When heated it melts, when highly heated it is decomposed, burning with- out leaving a residue. . A small quantity added to H2SO4 and gently heated is decomposed, with evolution of CO2, while alcohol and NH4HSO4 remain in sol. When heated with cone. sol. KOH ammonia is given off. If a little be dissolved in water together with some Na2COg and a minute quantity of iodin and warmed, yellow crystals of iodoform are produced. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 101 (k) If it at first melts and at red heat is decomposed without burning it may be (1), if without odor, Chloral- formamide; (2) if with odor of SO2, Sulfonal or Trional. Chloralformamide, Chloralamide.-It is soluble in water. It is not affected by dilute acids. Its solution is decomposed when warmed with KOH; it becomes turbid, then clear, and gives off chloroform. Sulfonal, Sulfomethane, Diethylsulfondimethylmethane.- Slightly sol. in cold, readily in hot water. When heated it melts. At a red heat it is consumed and SO2 is evolved. When heated with an equal weight of powdered char- coal, the disagreeable odor of mercaptan is developed. When heated with dry NaC2HsO2, gaseous H2S is evolved. Trional, Sulfonethylmethane.-The tests for trional are the same as those described for sulfonal. It differs in solubility, being soluble in 195 parts of water at 77° F. while sulfonal requires 360 parts of water. It is also more soluble in ether and in alcohol than sulfonal. Trional has a bitter taste; sulfonal is tasteless. (Z) If it at first melts and finally upon increasing the heat volatilizes or sublimes, it may be Resorcinol, Cam- phor Monobromated, Guaiacol Carbonate; and if it has a phenol-like odor, Betanaphthol, or if an aro- matic odor, Salol, Guaiacol, or Terpin Hydrate. Resorcinol, Resorcin.-It is very sol. in water, alcohol, ether and glycerin, slightly sol. in chloroform and in CS2. Its aqueous solution treated with a few drops of Fe2Cle sol. = a bluish color, changing to brownish-yellow on adding NH4OH. A small quantity heated with KOH sol. and a drop of chloroform gives a bright red color (due to formation 102 QUALITATIVE CHEMICAL ANALYSIS. of rosolic acid). The addition to this of a slight excess of HC1 changes the color to pale yellow. On heating a fragment with a grain of tartaric acid, and 10 drops of H2SO4, a thick red liquid results, which becomes pale yellow when diluted with water. Camphor Monobromated.-Almost insol. in water, freely sol. in volatile solvents and in cold cone. H2SO4. When heated it melts and sublimes. If a few crystals are fused in a dry test-tube with metal- lic Na, the residue dissolved in water and acidulated with HNO3 gives with AgNO3 sol. a copious white ppt. It has a camphoraceous odor and taste. Guaiacol Carbonate.-A white, odorless, tasteless powder, insol. in water, very sol. in chloroform, less sol. in alcohol, and in ether. It fuses at 87° C. It is decomposed when treated with an alcoholic, KOH sol., and from the sol. so obtained guaiacol may be separated on the addition of an acid, and identified by appropriate test. Betanaphthol, Naphthol U. S. P. 1890-A crystalline or pale buff-colored or colorless powder, having a faint phenol-like odor. Very sparingly sol. in water, very sol. in volatile solvents and in alkali-hydroxid solu- tions. A cold sat. sol. mixed with NH40H = a faint bluish fluorescence. A sol. of betanaphthol in KOH sol. (1:4) treated with a little chloroform and heated gives a blue color changing to green and then to brown. An aque- ous sol. treated with Fe2016 gives a greenish color, and after some time white flakes separate which turn brown when heated. Salol, Phenyl Salicylate-N white, crystalline powder, having a faint aromatic odor. Insol. in water, very sol. in the volatile solvents. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 103 With Fe2C16 a violet color is produced. If a few grams of salol be dissolved in warm NaOH sol. and the resulting sol. acidified with HC1, a ppt. of salicylic acid forms, and the odor of phenol is recognizable. Guaiacol.-A colorless crystalline solid or a colorless refractive liquid having an agreeable aromatic odor. Sol. in 53 parts of water, and in alcohol and ether in all proportions, and in acetic acid. The addition of Fe2Cle to an alcoholic sol. of guaiacol (1:100) = an immediate blue color changing to green and then to brown. Terpin Hydrate.-(a) It melts when quickly heated, and sublimes in fine needles. When strongly heated on platinum it burns with a bright smoky flame leaving no residue. (6) If to its hot aqueous sol. a few drops of H2SO4 be added, the liquid will become turbid and develop a strongly aromatic odor. Step VII.-If the substance is a liquid, possessing a charac- teristic odor, limpidity or viscosity, place about 1 cc. in a test-tube and apply gentle heat (water-bath). If it is com- pletely volatilized, look for it under A. If it is not com- pletely volatilized by gentle heat look for it under B. Step VIII.-If the substance comes into Class A, place 1 cc. of it into a test-tube and add 10 cc. of water, and note if it is miscible or not. (a) If it is miscible, it may be Acetaldehyd, Acetic Ether, Ether, Paraldehyd, Formaldehyd, Ethyl Alcohol, Methyl Alcohol. (6) If it is not miscible or soluble in 10 parts of water or more, it may be Chloroform, Benzin, Benzene, Cinnaldehyd, Amyl Alcohol, Amyl Nitrite, Benzo,l- dehyd. 104 QUALITATIVE CHEMICAL ANALYSIS. Class A. Division a. Liquids Miscible with Water. Ethyl Alcohol, Grain Alcohol.-A colorless, mobile, volatile and inflammable liquid. Miscible with water in all proportions. The Oxidation Test. To the alcohol add some K2Cr2O7 and a small quantity of H2SO4, and heat = a greenish color and an odor of aldehyd. 6C2H5OII + K2Cr2O7+4H2SO4 = K2SO4 + Cr2(SO4)3 + 6C2H3OH + / H2O» Aldehyde. The Acetic Ether Test. To a small portion of the alcohol add some KC2H3O2 and a little H2SO4'and warm the mixture = an odor of apples due to formation of acetic ether. kc2h3o2+c2h6oh+h2so4=khso4+c2h5c2h3o2+h2o Acetic Ether. The Iodoform Test (Leiben). Warm a small quantity of the alcohol with KOH and add some solution of iodin = a yellow ppt. of iodoform, forming slowly. Detects 12:000. C2H5OH+18+6K0H = CHI3 + KCOOH+5KI+5H2O Iodoform. Potass formate. The Molybdic Test. A 10% sol. of molybdic acid in strong H2SO4 warmed with the alcoholic liquid = a blue color. Detects 1:1000. Methyl Alcohol, Carbinol, Wood Alcohol.-A colorless volatile, inflammable liquid having a characteristic odor, and mis- cible with water in all proportions. It forms with dry CaCl2 a crystalline compound. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 105 The Salicylate Test. To a concentrated solution of sodium salicylate add some methyl alcohol and a few drops of H2SOi, and warm the mixture = an odor of oil of winter- green (methyl salicylate) develops: hc7h5o3+ch3oh=ch3c7h5o3+h2o. Methyl Salicylate. Methods for the Detection of Methyl Alcohol in Grain Alcohol, Pharmaceutical Preparations, Beverages, etc. The Resorcinol Test. A spiral of copper wire is heated to redness and plunged into the liquid. One drop of a 0.5% aqueous resorcinol solution is added and the mixture floated on cone. H2SO4. A rose-red zone at line of contact = methyl alcohol; above the zone a scanty white or pinkish-white coagulum appears which finally separates and rises in purplish flakes. Similar reactions are given with tertiary-butyl alcohols, di- methylethylcarbinol and formic acid, but the succession of colors and the deportment of the flaky coloring matter are different. If the methyl-alcohol solution is very dilute, repeat the immersion of the copper-wire coil several times. If the solution is concentrated, it should be diluted so as to be about 10% by volume. (Mulliken and Scudder, Am.. Ch. J., Vol. XXI., 226.) The Phloroglucin Test. The oxidation of methyl alcohol is the same as in the foregoing; acetaldehyd is removed by adding to the liquid remaining in the test-tube 6 cc. of a 3% H2O2 sol. and filtering into a porcelain dish. After 3 minutes add 2 cc. 10% sol. of Na2S2O3, and then 3 cc. of a phloroglucin sol. made by dissolving 1 grm. of phloro- glucin and 20 grm. of NaOH in water to make 100 cc.= a bright red color develops if methyl alcohol is present, the intensity of the color being in some degree proportionate 106 QUALITATIVE CHEMICAL ANALYSIS. to the quantity of methyl alcohol present. Authority same as preceding test. Prescott's Modification of the Foregoing Tests (see A. J. of Ph., Vol. 77, 108, Sadtler). The spirit tested should be diluted to about 10%. The copper wire is plunged into the liquid, held there for a second or two, then withdrawn and dipped into water to cool. This is repeated 5 or 6 times, the test- tube being immersed in cold water to keep contents cool. The liquid is then filtered into a wide test-tube and gently boiled to drive off acetaldehyd. The boiling should be continued until no odor of acetaldehyd is perceptible. Then the liquid is poured into a white porcelain dish and 1 cc. of the phloroglucin-alkali solution described in previous test added. A deep-red persisting color = methyl alcohol (formaldehyd reaction); a pale or slightly yellowish-red fading rapidly is due to acetaldehyd and indicates only ethyl alcohol. The Rimini Test, Modified (Haigh, Ph. Rev., Oct., 1903). The oxidation of the methyl alcohol and the removal of acetaldehyd by boiling is effected as in foregoing tests. Then 1 cc. of a dilute sol. of phenylhydrazine hydrochlorid is added, followed by a few drops of a fresh sol. of sodium nitroprusside and finally by 1 cc. of 50% sol. of NaOH; if formaldehyd is present a light-blue or green color results, de- pending upon the amount of CH3OH present. If the latter is absent, the color is greenish yellow. The method in which resorcinol is used seems to be the most satisfactory, and the new U. S. P. method is based upon its use. The Resorcinol Test of the U. S. P., 8th Dec. Revis., is in sub- stance as follows: 1 cc. of the spirit is diluted with water to make 10 cc. If the alcohol is already diluted, a corre- spondingly larger volume of it should be taken and diluted to 10 cc., so that the proportion of alcohol in the liquid shall not be more than about 10% by volume. A copper- wire spiral (of stated dimensions) should be heated to QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 107 redness in a flame free from soot, and plunged quite to the bottom of the spirit in a test-tube and held there for a second or two, then withdrawn and dipped into' water to cool. This is repeated 5 or 6 times, immersing the tube in cold water to keep down the temperature of the liquid; it is now filtered into a wide test-tube and gently boiled, until the odor of acetaldehyd is no longer clearly distinguished. The liquid is now cooled, and to it added 1 drop of aqueous solution of resorcinol. A portion of this liquid is then floated upon cone. H2SO4 in another test-tube, being careful that the liquids do not mix. This tube, after standing 3 minutes, is slowly rotated, and at the line of contact a bright rose-red ring will appear and indicate methyl alcohol. Miller's Test. (Oxidation with Dichromate) P. J. Tr., 2d Ser.. VII, 318. Take | ounce of the spirit, distil off about 1 dram. Then place in a small distilling-flask 30 grains of K2Cr2O7, 4 fl. drams of water, and 30 minims of cone. H2SO4. To this add 30 to 40 minims of the above distillate and let stand 15 minutes. Then distil off about | of the quan- tity, and to the distillate add Na2CO3 in slight excess, and boil down to 2 fl. drams. Then acidulate feebly with HC2H3O2 and add 1 grain of AgNO3 in 30 minims of water and heat gently. If the liquid merely darkens, but remains trans- lucent, CH3OH is absent, but if a copious ppt. of metallic silver falls and a thin film of silver lines the tube, methyl alcohol (CH3OH) is present. Note.-This test depends upon oxidizing CH30H to formic acid (HCOOH), which reduces silver. CH30H + O2 = HCOOH + H2O. The ethyl alcohol present is oxidized to acetic acid, which does not reduce silver. Aldehyd, which is produced at the same time and which does reduce silver, is removed by boiling with Na2CO3. 108 QUALITATIVE CHEMICAL ANALYSIS. dicker's Method (Am. Dr., Meh. 25, '01, and Ph. Rev., '01, 117). This method is based upon the oxidation to formalde- hyd by a heated copper-wire spiral, and has the advantage of rapidity. Pour 4 to 8 cc. of the spirit into a test- tube and warm gently; immediately insert into the tube (not into the liquid) a copper-wire spiral which has been previously heated to dull redness; withdraw and reinsert the spiral several times, and it will be observed that a strong odor of jormaldehyd is evolved, while the spiral will change in color from black CuO to red Cu upon in- serting it, and will resume its black color each time it is withdrawn into the air. Note.-Heating the copper wire oxidizes it to CuO. The warm methyl-alcohol vapor reduces the CuO to Cu .and is itself oxidized to formaldehyd. CH3OH + CuO = HCOH + H2O + Cu. Ethyl alcohol reduces CuO in the same manner, but the odor of formaldehyd and of formic acid distinguishes the methyl alcohol. Acetaldehyd.-Colorless, limpid, inflammable, possessing a fruity odor. Boiling-point 20.8° C. Miscible with water, alcohol, ether, and benzin. (1) With solution of Ag2O in ammonia, gives a bright mirror of silver on warming. KOH facilitates the reaction. (2) It reduces Fehling's solution on being boiled, deposit- ing a red ppt. of Cu2O, and being thus converted into acetic acid: C2H4O + O = HC2H3O2. (3) Heated with KOH it acquires a brown color. (4) Rosaniline solution bleached by SO2, gives a pinkish- violet color with aldehyd. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 109 Paraldehyd.-A limpid liquid, colorless, possessing an odor resembling that of aldehyd. Soluble in 8 parts of water. Boils at 124° C., evolving inflammable vapors. Distilled with dilute H2SO4 it is again converted into aldehyd, of which paraldehyd is a polymer; its formula is C6H12O3 (which is the formula of aldehyd (C2H4O) taken three times). (1) Boiled with KOH it gives no brown color (distinction from aldehyd). (2) Heated with Ammonio-Argentic-Nitrate, it pro- duces a mirror of metallic silver. Formaldehyd, Formalin, Formic Aldehyd (CHOH).-Miscible with water and alcohol, possessing a pungent odor of hamamelis extract; highly antiseptic liquid. (1) With Sulfo-ferric-chlorid Reagent (Lyons) (Tinct. Fe2Cl6, U.S.P. 1 p. strong H2SO4, 25 p.). Underlay 2 cc. of the solution to be tested (distillate if necessary) with 2 cc. of the Sulfo-ferric-chlorid solution as carefully as pos- sible = a pink to violet-blue zone will be formed; reaction very delicate. (2) With the Morphine-sulfuric Reagent (Morphine 0.12 gm. in strong C. P., H2SO4 3 cc.). Underlay the distillate or a solution of CHOH with 2 cc. of the reagent; a purple- red color changing to violet will form. (By mixing 3 drops of 40% Formaldehyd with 3 cc. of pure strong H9SO4, a reagent is obtained which gives a similar reaction with Morphine (very reliable). Heated with ammonio-argentic-nitrate solution = a gray ppt. of metallic silver and a deposit of silver in form of mirror on sides of tube. To a little H2SO4 in which some salicylic acid has been dissolved, the addition of two drops of formalde- hyd solution will produce a permanent deep red color on warming. Ether, Ethyl Oxid.-A colorless, mobile, highly inflammable liquid of characteristic odor, boiling at 35.5° C., miscible 110 QUALITATIVE CHEMICAL ANALYSIS. with 10 times its volume of water, and very readily miscible with alcohol, chloroform, benzin, benzene, and oils. It dissolves fats and resins. Acetic Ether, Ethyl Acetate.-A colorless, limpid, inflammable liquid, possessing a fragrant acetous odor resembling that of apples. It boils at 72° C., and is miscible in all propor- tions with alcohol and with 7 parts of water. Boiled with KOH sol. the residue gives reactions of acetates. Distilled with KOH sol. alcohol is produced, and distils over, and the distillate gives the reactions for ethyl alcohol: C2H5C2H3O2 + KOH = KC2H302 + C2H5OH. Class A. Division b. Liquids not Miscible with Water. Chloroform, Trichlor Methane, CHC13.-A heavy, clear, colorless, mobile liquid of a characteristic odor. It is very volatile, not inflammable, and not miscible with water. (1) To a small quantity of chloroform in a test-tube add some alcoholic sol. of NaOH, and a drop or two of aniline, and warm gently. There will be developed a very offensive odor of phenylisocyanid. (2) Boil a few drops of chloroform with KOH sol. and add a fragment of resorcinol. An intense red color appears (rosolic acid). (3) A few drops of chloroform, heated with a sol. of betanaphthol in strong KOH sol. develops a fine blue color, changing to green and brown. Benzin, Petroleum Ether.-A clear, colorless liquid, of a strong characteristic odor, resembling that of kerosene. It is very inflammable, and is not miscible with water. It boils at 45° to 60° C. Benzene = Benzol = Coal-tar Benzene.-A limpid liquid possess- ing an aromatic benzin-like odor. Should not be con- founded with petroleum benzin. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. Ill Boiling-point 80° C. Miscible with alcohol, ether and chloroform, insoluble in water. Chemical formula C6H6. (1) Mixed with strong HNO3 (avoiding overheating) nitrobenzene (oil of mirbane), C6H5NO2, is formed, which, poured into cold water, separates in oily drops possessing the characteristic odor of essential oil of bitter almonds. (2) Mixed with strong H2SO4 and boiled with KOH, a phenolsulfonate is obtained which should be tested for. Amylic Alcohol (Fusel Oil). A limpid oily liquid possessing the odor of whiskey; miscible with alcohol, but very spar- ingly with water. Boils at 127° C. (1) Warmed with dilute H2SO4 and NaC2H3O2, it forms amyl acetate (C5HnC2H3O2) possessing the odor of pears, and known as "pear oil." (2) Distilled with H2SO4 and K2Cr2O7 and the distillate boiled with KOH, it forms potassium valerate. Apply the tests for valerates. Amyl Nitrite, C5HnNO2.-A clear yellowish liquid of an ethereal banana-like odor. Insol. in water. Freely miscible with alcohol or ether, very volatile even at low temperature and very inflammable, burning with a smoky flame. When mixed with potassium iodid and a drop or two of sulfuric acid, iodin is liberated, and colors starch blue. Benzaldehyd, Benzoic Aldehyd.-A colorless, strongly refrac- tive liquid having an odor like that of essential oil of bitter almonds. Insol. in water. It is converted into ben- zoic acid by oxidation. Class B. Phenol, Carbolic Acid-Phenic Acid.-The liquefied carbolic acid is a colorless liquid having a peculiar characteristic aromatic odor, miscible with water, and readily sol. in 112 QUALITATIVE CHEMICAL ANALYSIS. alcohol, ether, chloroform and the alkalies. It cauterizes and whitens the skin when concentrated. Creosote, an almost colorless or yellowish (pinkish, or brown if impure), highly refractive, oily liquid having a penetrating, smoky odor; sol. in HC2H3O2. Phenol. Creosote. The Bromin Test.-Its aqueous sol. yields with bromin-water a white ppt. of tribromphenol, which at first redissolves, but on adding more of the reagent becomes permanent. The Ferric-Chlorid Test.-10 cc. of aqueous sol. of phenol (l:100) + l drop of Fe,Cl6 sol. The sol. be- comes violet-blue, and the color is permanent. The Collodion Test-Equal volumes of phenol and collodion, stirred to- gether in a dry test-tube, will form a permanent coagulum. This also occurs with albumen. The Glycerin Test.-1 volume of cold liquefied phenol forms with 1 vol. of glycerin a clear liquid, which is not rendered turbid on the addition of 3 vols. of water. The KOH Test.-Not so with phenol. Solidification Test.-Phenol sol. solid- ifies when cooled. 4 parts of phenol sol. mixed with 1 part of NH4OH and a few drops of NaClO added and gently warmed = a blue to green color. Add H2SO4 to some benzaldehyd until the latter darkens, then add some phenol, and a red color is pro- duced; now add some K0H = a violet. The Bromin Test-Its aqueous sol. yields with bromin-water a reddish- brown ppt. The Ferric-Chlorid Test.-The liquid develops a violet tint, which is transient, changing rapidly to green- ish and brown, and forming a brown ppt. The Collodion Test.-No permanent coagulum results. The Glycerin Test.-1 vol. of creo- sote forms with 1 vol. of glycerin a clear liquid, from which } vol. of water will cause separation of a creosotic layer equal to more than 1 vol. and render liquid turbid. The KOH Test.-1 cc. of creosote mixed with 10 cc. of KOH in abso- lute alcohol (1:5)= a solid crys- talline mass. Solidification Test.-Creosote cooled to -I0 F. does not solidify, but it gelatinizes. ■Glycerin. Glycerol Propenylalcohol.-A clear, colorless, thick, syrupy liquid, smooth to the touch, sweet to the taste, odorless, producing a sensation of warmth in the mouth. It absorbs moisture; sol. in all proportions in water and QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 113 alcohol, but not sol. in ether, chloroform, carbon disulfid, benzin or oils. (1) The Borax-Bead Test. Add a few drops of glycerin to a little powdered borax; mix and dip the looped end of a platinum wire into the mixture, and hold in a Bunsen flame = a transient green color. (2) The Acrolein Test. Heated alone or with H2SO4 to a high temperature an irritating odor of acrolein is produced. (3) The Borax Test. A piece of blue litmus paper is shaken in a test-tube with a solution of borax, and a few drops of glycerin added. The litmus paper immediately becomes red. This is due to the liberation of boric acid by the glycerin. The addition of a little bicarbonate of soda to this mixture will cause effervescence. (4) The Permanganate Oxidation Tests. Glycerin in a strongly alkaline sol. is oxidized by KMnO4 and converted into oxalic acid. Take 1 cc. of a weak sol. of glycerin, make it strongly alkaline with KOH, and add an excess of a saturated sol. of KMnO4, i.e. until the mixture is blackish. Boil and add some Na2SO3 to destroy excess of'KMnO4, then filter, acidulate with HC2H3O2, and add CaCl2 = a white ppt. of CaC2O4 forms. C3H6(OH)3+4KMnO4 = K2C2O4 + K2CO3 +4MnO2+4H2O Potassium Oxalate. K2C2O4 + CaCl2 = CaC2O4 + 2KC1 Calcium Oxalate. Note. If the foregoing tests are to be applied to any mix- ture containing organic matters, a portion of the latter is evapo- rated to dryness at a temperature below 100° C. and the glycerin extracted from the residue by means of ether. The ethereal solution is then evaporated and the tests applied to the residue. 114 QUALITATIVE CHEMICAL ANALYSIS. Nitrobenzene = Nitrobenzol (Oil Mirbane). A limpid, yellowish, oily liquid, possessing the odor of essential oil of bitter almonds. (1) Placed in contact with zinc dust and dilute H2SO4, it is decomposed into aniline and water: ♦ C6H5NO2+3H2 = C6H5NH2 + 2H2O. (2) Heat the aniline solution as obtained above with a few drops of CHC13 and KOH. The characteristic odor of phenylisocyanid will be recognized. (3) Drop a small crystal of KC103 into some nitrobenzene,, and underlay this with H2SO4; a violet color will develop. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 115 90. SCHEME FOR THE IDENTIFICATION OF ACETANILIDE, PHENACETIN, QUININE SULFATE.- F. S. Hyde.* Solution of substance in water. Pure substance. Melting- point. C. Solubility in water. Boiled with excess of KOH and a few drops of chlo- roform Ferric chlorid. Dilute nitric acid. Bromin-water. Acetanilide * (Phenylacetamide) CeH5NH.COCH3. 113° Soluble in cold; more so in hot. Odor of isonitrile. Yellow solution. Red on boiling. Colorless. White crystals. Para-bromo- acetanilide. Exalgine (Methyl Phenylacetamide) C6H5N.CH3.COCH3. 101° Not very soluble, cold; easily solu- ble, hot. No odor of iso- nitrile. Class of secondary amines. Yellow solution. Cloudy red on boil- ing. Colorless. No precipitate. Phenacetin (Acetylparaamidophenetol) C1H4.OC2H5.NH.CO. 135° Soluble with difficulty. Odor of isonitrile. Yellow solution. Blood-red on boil- ing. Cloudy yellow solution. Crystals ofnitro compound. No precipitate. Phenecoll hydrochloride (Glycocollparaamidophene- tol) ft TT OC2H5. ^6H«< NH.COCH2.NH2.HC1. No. M.P. HC1 Comp. Very soluble. Odor of isonitrile. Yellow solution. Darkens and orange precipitate on boiling. Colorless. No precipitate. Salol (Phenyl salicylate) C6H4.OH.COO.C6H6. 43° Soluble with difficulty. No odor of iso- nitrile. Yellow solution. Yellow solution. Blood-red on boil- ing. Colorless. No precipitate cold; white cloudy compound on boil- ing. Resorcinol ( Metadioxybenzene ) CeH4(OH)2. 118° Easily soluble. No odor of iso- nitrile. Carmine- red solution. Dark violet. Yel- lowish on adding drop of sulfuric acid. Yellow solution. Yellowish precipi- tate dissolving im- mediately. Quinine sulfate C20H24N2O2.H2SO4. Slightly soluble. With few drops of sulfuric acid dis- solves with blue fluorescence. Base precipitates and dissolves on heating. Yellow solution Colorless with blu- ish fluorescence. Dry substance on porcelain with weak bromin- water gives green coloration on add- ing two or three- drops ammonia- water = Thallieo quin test. Antipyrine (Phenyldimethylpyrazolon) HOC3N2(CH3)2C6Hs. 113° Soluble. Nothing. Blood-red. Disap- pears on adding a drop of sulfuric acid. Colorless. Y ellowish-white precipitate. * J. Am. Chern. Soc., Vol. XVII, page 933. 116 QUALITATIVE CHEMICAL ANALYSIS. 9i. PROFESSOR E. H. BARTLEY'S* SCHEME FOR THE IDENTIFICATION OF ORGANIC SUB- STANCES COMMONLY USED IN PHARMACY, MEDICINE, AND THE ARTS. Inspection. Observe fhe color, consistency, if a liquid, odor, taste, etc. 1. The Color of definite chemical compounds of organic origin is characteristic only when they are in a pure state. When impure, the color is of little service. Note. The first thing to determine in any given substance is whether it is a definite compound or a mixture. If a liquid, this is best determined by distillation when this is possible, having care at the same time to determine its boiling-point, or if more than one liquid can be distilled off, the boiling- point of each, and collecting each by itself. If the substance be a solid, it is best to examine it under a microscope of low power to determine whether it be homogeneous, crystalline, amorphous, or a mixture. If a mixture, it may often happen that the substances may be separated by a proper choice of solvents, observing the effects under the lens. Crude powdered drugs and bodies like starch, pollen, talcum, etc., may be readily identified in this way. 2. The Consistency of a liquid, whether viscid, oily, mobile, volatile, fixed, etc., both cold and warm, is of much importance, and often gives a clue to its identity. 3. The Odor of some organic compounds, especially the liquids and some of the solids, is so characteristic as to be of great service in giving a clue to their identity, or to the exclu- sion of certain substances. When the substance has a distinct odor it is of great service. Some liquids give off their char- acteristic odor better while warm than when cold. When the * From hectographed sheets as used by the post-graduate class in the Brooklyn College of Pharmacy. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 117 odor is identified, it is best to compare that of the substance under examination with that of a known substance which it is known to resemble. Odors are described as ethereal, alcoholic, pungent, ammo- niacal, terebenthinate, camphoraceous, aromatic, tarry, putrid, sulphurous, etc. 4. The Taste of some organic compounds is highly char- acteristic, especially in dilute solutions. Tastes are described as: Sweet, as that of the higher alcohols, glycerin, mannit, etc., the sugars and saccharin. Sour, as that of the soluble acids and acid salts. Bitter, as that of the alkaloids, glucosides, tannic, gallic, and picric acids, and some resinous and bitter principles of plants. Aromatic, as that of certain essential oils or their deriva- tives, the aromatic hydrocarbons or their derivatives, the phenols, cresols, aniline, and their derivatives. Burning, as that of alcohol, chloroform, carbolic, etc. The burning taste is usually only obtained with the pure substance. Camphoraceous, terebenthinate, tarry, empyreumatic, and similar terms are descriptive by comparison with well-known substances. Caution! Never taste a pure substance of which you know nothing. Make a dilute solution in alcohol or water (about 1%) and then taste cautiously. Separation of Organic Compounds Into Groups. A. Heat a small fragment of the dry substance on a piece of platinum foil or fine iron-wire gauze. 1. It evaporates, but neither chars nor ignites: it is water. If a residue is left, note its behavior on heating. 2. It chars or ignites and burns = an organic body. Leaves a residue = organic salt of a metal. 118 QUALITATIVE CHEMICAL ANALYSIS. Residue alkaline to litmus and effervesces with HC1 = alkaline metal. (See flame reactions under B.) It chars and gives odor of burning hair or a pungent tarry odor = nitrogenous matter or an alkaloid. 3. It does not char and does not burn away inorganic. 4. It chars and gives odor of S02 = organic compounds rich in sulfur. (See N.) If the substance is a liquid, note whether it gives off soot when burning. Remove from flame after ignition takes place and observe odor of the smoke. Notes: Almost all hydrocarbons, aromatic compounds, and complex organic compounds containing more than 4 carbon atoms give off soot in burning. The lower alcohols containing less than 5 carbon atoms, the simpler ethers, aldehyds, ketones, and other derivatives of the methane series having less than 4 carbon atoms usually give off no soot in burning. B. Heat a fragment of the substance, or a drop of the liquid, in the loop of a clean platinum wire. 1. The flame is tinged with green: Halogen in absence of Ba or boric acid. If green is obtained use copper wire previously heated in outer edge of Bunsen flame, when the green color is much brighter if halogens be present. 2. The flame is violet: Salts of potassium. View through cobalt glass. Substance leaves residue, test as in A. 3. The flame is yellow: Sodium. 4. The flame is red: Lithium or strontium. C. The Detection and Removal of Water.-If the substance is a solid it should be dried well before treatment as described below in E. Liquids: (1) To 5 cc. of the liquid add 0.5 to 1 grm. of fused and pulverized K2CO3, shake well, and let stand for a half-hour. If water be present the K2CO3 will entirely dissolve, or will dissolve in the water present and separate as a layer at the bottom. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 119 Or, (2) To 5 cc. of the liquid add 1 grm. of recently ignited (dehydrated) copper sulfate. The presence of water is shown by the CuSCU assuming a blue color within a half-hour. Effervescence (1) indicates the presence of an acid or acid salt. A white precipitate is most likely, though not always, due to the precipitation of an alkaloid. D. // water be present, boil a portion of the liquid in a test-tube and test the inflammability of the vapor in the mouth of the tube, to prove the presence or absence of a volatile organic liquid. If no inflammable vapors are obtained, evaporate a few cc. in a watch-glass on a water-bath to dry- ness or to a syrupy consistency. The residue, if any, or the concentrated liquid free from water, may be tested as below described. If inflammable vapors are obtained, distil off a portion of the volatile liquid and apply the tests to the distillate. The liquid to which the following tests are applied must first be freed from water, by agitation with fused K2CO3 or CaCO, and allowed to stand a half-hour. Ultimate Qualitative Analysis of Organic Compounds. All non-gaseous bodies combustible in the air are organic and hence contain carbon and hydrogen. E. To Detect other Elements.--Put in a clean dry matrass of hard glass about 0.1 grm. of clean sodium and heat carefully over a flame until a part of the metal is converted into vapor, and let fall two or three drops of the liquid, or a corresponding amount of the solid, directly upon the fused metal. Allow the mixture and tube to cool, add a few drops (1 cc.) of alcohol to dissolve unchanged sodium, then a few cc. of distilled water, and filter through a small filter. Test the solution as follows: For sulflds, with a copper coin, or by a drop on filter-paper wet with lead acetate solution. 120 QUALITATIVE CHEMICAL ANALYSIS. For sulfur and nitrogen together, by acidifying with HC1 and adding Fe2Cl6, when the red color of ferric sulfocyanid will appear. For nitrogen without sulfur, by testing for cyanids by adding NaOH and a mixture of ferrous and ferric salts, and then acidifying with HCl = blue color. For chlorin, with HNO3 and AgNO3, when S is present, boiling with excess of NHO3 before adding the AgNO3; soluble in NH40H. For bromin and iodin, by acidifying with HC1, adding chlorin water, and then chloroform or starch solu- tion. 1 For halogens (confirmatory), heat a loop of copper wire in the outer flame of Bunsen burner, cool, dip in substance, and heat again = green flame, halogen. For nitrogen (confirmatory), heat the substance with soda- lime-most nitrogenous compounds, except nitro com- pounds, give off ammonia-and test vapors with moist reddened litmus paper in mouth of tube or glass rod wet with HC1. Nitrogenous animal matter usually gives off the odor of burnt horn or hair on being heated dry; alkaloids and amin derivatives give a pungent tarry odor. Having determined what elements are present, we next determine the class or group to which they belong. F. Acids and Bases.-Test reactions with red and blue litmus for free acids, acid salts, and bases. Solids must be brought into solution in water or alcohol. Most acids are soluble enough to react acid with litmus. Confirm by warming with K2CO3 or Na2CO3 = effervescence. Organic bases are usually nitrogenous, and aliphatic amins, aromatic amins with the amid group in the side chain, free alkaloids or some of the artificial bases. In the last case they are black or dark liquids of a strong offensive odor. All these bodies except aliphatic amins are insoluble QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 121 in water, but dissolve as a rule in dilute acids to form crystal- lizable salts. When heated with NaOH solution the amids, imids, and nitrils evolve NH3. Amins do not evolve NH3 with NaOH solution; give pungent fumes at red heat. Amins containing the lower alcohol radicals are soluble in water and dissolve in weak acids to form salts. These salts as well as the amins containing higher radicals are soluble in alcohol. This distinguishes them from ammo- nium salts. The substance contains no nitrogen.-To 2 cc. of the thor- oughly dried liquid in a dry test-tube add a small fragment of metallic sodium. If no action ensues warm the solution. Viscid liquids and solids should be dissolved in anhydrous alcohol-free ether or in petroleum ether before adding the sodium. Bodies containing hydroxyl slowly evolve hydrogen with metallic sodium. Besides hydroxyl compounds, some aldehydes, ketones, esters, and amids evolve hydrogen. The halogen compounds of methyl and ethyl evolve gaseous hydrocarbons. A few hydroxyl compounds, as resorcinol and salicylic acid, do not give off hydrogen with sodium. Rapid evolution of hydrogen will suggest water as an impurity. The acids will have been identified under F. Amids will have been detected under F, and will contain nitro- gen, which excludes them from this group of compounds. The halogen compounds will have been detected by flame reaction under E. The odor of the original substance will be of assistance here. The aromatic compounds (phenols, cresols, tannins, etc.) and hydrocarbons will have been suspected from giving 122 QUALITATIVE CHEMICAL ANALYSIS. soot in burning under A, and from odor and oily appearance if liquid. No hydrogen is given off by hydrocarbons-No action, even on warming, will then generally indicate that the substance is not an alcohol, a phenol, or an acid. H. Treat a portion of the original solution, or liquid, with a few drops of Fe2Cl6; the solution must be neutral. Phenol, resorcinol, and salicylic acid give violet, orcin blue-violet, pyrocatechin a green, and pyrogallol red and a blue with FeSO4 and Fe2(SO4)3. Naphthol, the nitrophenols and para oxacids do not give a color with Fe2Cle. I. Treat a small portion of the substance on a watch-glass with strong H2SO4J or, if a liquid, add 2 cc. of C.P. H2SO4 to 1 cc. of liquid, keep cool by immersion in water, and shake well, and observe any action or change in color. Solids may not be acted on, may be dissolved without change, may be dissolved with change of color, or may be dehydrated and charred. Liquids may not be acted upon (as monatomic, primary alcohols and saturated hydrocarbons), may be dissolved without change, may combine with the acid with evolution of heat, or may be decomposed with blackening, etc. Cold H2SO4 does not affect saturated or aromatic hydrocarbons or their haloid derivatives; most other compounds are either dissolved or decomposed. After observing the action in the cold, warm and note any change. Hot H2SO4 esterifies monatomic primary alcohols, and unites with unsaturated hydrocarbons of aliphatic series and aromatic hydrocarbons and most of their deriva- tives. Pour the mixture into twice its volume of water and measure the volume of any separated liquid to see if it has suffered any loss in volume. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 123 Separate the undissolved portion, if a liquid, and reserve for further tests. J. To another portion of the liquid known to contain no nitrogen, or to the solid brought into solution in chloro- form or carbon tetrachlorid, add, drop by drop, a distinct excess of bromin in solution in water, or in chloroform or CC14. 1. A precipitate (tribromphenol) indicates a phenol (but few exceptions). Many aromatic amins also give this reaction (see Fe2Cl6 reaction under H). 2. An instantaneous decolorization without subsequent pre- cipitate and without evolution of HBr indicates addition, and probably unsaturated hydrocarbons. 3. Decolorization with evolution of HBr shows substitution and may occur with an aldehyde, a ketone, a phenol, or an amin. In last case without evolution of HBr. 4. Production of heat in oils. 5. No decolorization with saturated hydrocarbons, alcohols, or esters of fatty series. K. Test the solubility of the substance in water and then treat it with cold 10% solution of KOH and observe the result. 1. The substance dissolves in KOH solution, and also in pure water; no deduction can be drawn. 2. The substance is insoluble in water and soluble in 10% KOH = many esters, with separation of the alcohol, which may be detected by odor or by appropriate tests applied to distillate. Esters of higher alcohol radicals are not usually saponified by cold dilute KOH, but may be by heating the mixture. The alcohol will then usually separate as a distinct layer; the acid remains in solution as a salt of potassium = many organic acids and phenols (see F and H). AU free organic acids dissolve in cold KOH solution. After separating any alcohol or undissolved liquid or solid, acidify a portion of the KOH solution with HC1. 124 QUALITATIVE CHEMICAL ANALYSIS. Observe if any acid separates, or if on warming any acid odor develops; apply the regular tests for acids. 3. Neutralize a portion of the KOH solution and apply the usual tests for the acids. 4. Insoluble in water and insoluble in cold 10% KOH so- lution: Hydrocarbons, higher alcohols, ethers, some ' phenols, and phenol derivatives. L. If the substance is not affected by cold 10% KOH solution, heat a portion of it to boiling for three to five minutes with a strong solution of KOH. 1. The substance is not affected: Hydrocarbons, most alco- hols, ethers, etc. 2. The substance is dissolved and does not separate on cooling, or, if so, it has a different odor and behavior from original substances: Esters not saponified under K. 3, including the fixed oils, some phenols, cresols, and halogen compounds of hydrocarbon radicals. The halogens are not removed, as a rule, from the radical of substitution compounds. Aldehyds are generally decomposed by strong KOH, with formation of a hydrocarbon and potassium formate. The decomposition of aliphatic haloid compounds yields alcohols, and of aromatic halogen compounds they yield phenols or hydrocarbons. Dilute the solution formed by boiling with strong KOH, with 5 parts of cold water, and note whether there is a separation of a liquid, the formation of an emulsion, or a precipitate, and whether the liquid or solid thus separating resembles the original substance. M. 1. Whether solution or decomposition takes place in K or L, separate the solution of KOH from any undissolved substance and faintly acidify with HC1, and test the solution for organic acids. If a separation of a liquid or solid takes place on acidifying, this is an organic acid, a phenol, a cresol or QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 125 a resin. Formic, hydrocyanic, acetic, propionic, citric, tartaric, succinic, butyric, oxalic, meconic, valeric, malic, tannic, gallic, and picric acids will remain in solution after acidifying. Oleic, stearic, palmitic, the resin acids and other higher fatty acids, the phenols, cresols, and aromatic acids will separate on acidifying. 2. Acidify another portion of the KOH solution with HNO3 and test for halogens with AgNO3 in the usual way. The substance contains sulfur and no nitrogen.-The sub- stance gives off SO2 when heated on platinum foil, or gives the reaction for sulfur when heated with sodium: The substance is a sulfate, a sulfuric ester, a sulfite, a sulfurous ester, a sulfonic acid, a sulfone (sulfonal, trional, tetronal), a sulfid, a mercaptan, a thioaldehyd, a thioketone, or volatile oil of mustard. The sulfones give off SO2 when heated on platinum foil. When melted in a dry test-tube and then a little gallic or pyrogallic acid dropped in, it turns brown and gives off the odor of mercaptan. Sulfuric esters and sulfurous esters are easily saponified when heated with strong HC1, the latter giving off SO2. Barium chlorid gives a precipitate with the former after treating it with HC1. A sulfite gives off SO2 with HC1, and a sulfid gives off H2S. Sulfonic acid and sulfonates only decompose when fused with KOH or NaOH. The solution of the fused mass, after acidification with HC1, gives BaSO4 with BaCl2. Mercaptan will be recognized by its odor of garlic or asa- foetida. 126 QUALITATIVE CHEMICAL ANALYSIS. 92. SUMMARY OF NON-NITROGENOUS CLASSES OF ORGANIC BODIES. Organic Acids give acid reaction to litmus paper and are mostly soluble. Exceptions: Benzoic, salicylic, and fatty acids containing more than 4 carbon atoms (valeric 1 in 27 of water). Lower members have characteristic odors. Poly basic acids are usually soluble in water; higher fatty acids insoluble. For sulfonic acids see above. Free Nitrogen Bases react alkaline to litmus. Amins with lower fatty radicals, aromatic radicals, or alkaloids all combine with acids to form salts; they are usually soluble in water and all are soluble in alcohol. Alkaloids and amin bases when heated in the test-tube or crucible yield pungent, offensive vapors. The vapors of salts react acid with litmus paper held in mouth of tube. Morphine (alkaloid) gives an alkaline vapor. Hydrocarbons burn with a smoky flame, giving soot; are all insoluble in water, contain no nitrogen, and do not evolve hydrogen with sodium. Saturated hydrocarbons do not react with bromin or sulfuric acid, or KOH solutions. Unsaturated hydrocarbons dissolve in cold C.P. H2SO4 as well as most other compounds, except saturated and aromatic hydrocarbons and their halogen derivatives, and usually instantly decolorize bromin solution, without evolving HBr. Aromatic hydrocarbons form sulfonic acids with hot H2SO4 and dissolve. Alcohols.-Monatomic alcohols having less than 4 carbon atoms are miscible with water, and burn without giving off soot. All alcohols give off hydrogen with metallic sodium, and esterize with strong H2SO4 and heat, and form esters with organic acids, when salts of these acids are warmed with the alcohol and H2SO4. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 127 They are distinguished from phenols by reaction of latter with Fe2Cle and bromin water, and from aldehyds by their failure to restore the red color to a solution of fuchsin decolor- ized with H2SO3, or to form compounds with phenylhydrazin. Behavior with bromin water distinguishes unsaturated alcohol radicals from saturated; from one another by boiling- point, etc. Aldehyds. - Class identified by reaction with phenylhy- drazin and colorless fuchsin; also by reaction with strong KOH solution and with bromin. Evolve hydrogen with sodium. Not affected by H2SO4, except aldose group of carbohydrates. Form acids by oxidation with potassium permanganate, with separation of MnO2. Aldehyds reduce an ammoniacal solution of AgNO3 on heating to boiling. Ketones.-Acetone and most other ketones form pre- cipitates with phenylhydrazin. Cold concentrated H2SO4 either dissolves or destroys aldehyds and ketones. Sodium acid sulfite gives crystalline compound with acetone, and with all other ketones containing the group CH3CO. Acetone gives red color with a few drops of freshly made solution of sodium nitroprusside and ammonium hydroxid. Acetone gives iodoform with iodin in KI and NH4OH. Alcohols do not under these conditions, nor do aldehyds. Ethers.-Ammonia, alkalies, cold dilute acids, sodium, and PC15 have no action on simple ethers. Warmed with C.P. H2SO4 gives alcohol and alkyl sulfuric acid. The alcohol may be distilled off and tested. Neutralize the acid solution with BaCO3, filter, and evaporate to dryness. BaSO4 left; insoluble in HC1; or boil the filtrate from the BaCO3 with C.P. HC1, when a precipitate of BaSO4 will indicate the ethereal sulfuric acid and hence an ether. Esters.-These are easily saponified by warming with 10% KOH solution. The alcohol distils off, and acid detected, after 128 QUALITATIVE CHEMICAL ANALYSIS. neutralizing with HC1, by usual means. Boiling with strong HC1 also decomposes them in some cases. Halogen compounds of hydrocarbons of fatty series are decomposed by strong KOH solution. Boiling solution of alcoholic KOH sets free aromatic hydrocarbons from haloid compounds of these. Strong KOH solution gives soap with fats and oils. Acidification sets free fatty acid. Bromin reacts with great energy upon fats and oils. Fats and oils are insoluble in water and soluble in ether. Carbohydrates or Saccharids contain CH and 0. When heated on foil, they melt, char, swell up, and give off burnt-sugar odor, leaving voluminous charcoal (see A). They turn brown when heated with strong H2SO4 (see I). They effervesce with metallic sodium (see G). When their solutions are boiled with KOH solution they turn first yellow and then brown. They are generally soluble in water (except cellulose, lignin, and tunicin), but are insoluble in strong alcohol. When heated in matrass or dry test-tube they decompose and give off water, which condenses in upper part of tube. Vapors acid. Gums.-Soluble or partly soluble in water, and precipitated by alcohol. Watery solution viscid, and sticky on drying: Dextrin gives brown color with iodin; others give no color, except tragacanth, which often contains starch. Organo-metallic Compounds.-These compounds leave a very considerable residue on heating the substance on platinum foil. They char or turn black on heating, and then gradually become lighter in color except when the metal is iron. They are chiefly compounds of iron, bismuth, mercury, aluminum, silver, cadmium (salicylate), cesium (tartrate), calcium, boron (boric acid), sodium, strontium, magnesium, lithium, potassium, mag- nesium, manganese, uranium (acetate), and zinc. The metallic bases should first be determined by heating a portion of the substance until it chars, exhausting the charred QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 129 mass with nitric acid if lead, silver, or mercury be found, or with HC1 when these metals are found to be absent by a pre- liminary trial with HNO3. The HC1 solution is to be treated by the usual course of qualitative examination for the metals. When the metal has been proven to be sodium or potassium or lithium, we may at once proceed with the examination for acid radicals in the aqueous solution of the substance. When the metal is not one of the alkaline metals, treat the substance with dilute KOH solution and heat to boiling. Filter off any precipitate, render the solution acid with HC1. If a precipitate forms on making the solution acid, filter. The acid so precipitated may be benzoic, salicylic, stearic, palmitic, oleic, phenol, cresol, or naphthol. 93. IDENTIFICATION OF SCALED IRON COMPOUNDS* Joseph L. Mayer. Step I.-Heat about 1 gram of the substance in a porcelain crucible to dull redness, allowing free access of air. If an odor resembling that of burning sugar is given off, the substance is probably a citrate or tartrate. Confirm in Step IV. When all the combustible matter is consumed, dissolve out the soluble part of the residue with a few cc. of hot water, and filter. Test the filtrate with red litmus paper. The paper turns blue; sodium or potassium, or both are present. The paper remains unchanged in color; proceed to Step II. Divide the solution which has turned red litmus blue into two parts. (a) Heat on a clean platinum wire in a colorless flame: The flame becomes intensely yellow; sodium is present. Observe * Drugg. Cir., Feb. 1901. 130 QUALITATIVE CHEMICAL ANALYSIS. this flame through cobalt glass. If violet-red, potassium also is present. The flame is colored violet only; potassium is present. Con- firm under (&). (6) Add to the solution some test solution of sodium-cobalt nitrite: A copious yellow precipitate indicates potassium. Step II.-Dissolve a small quantity of the original sub- stance in water, acidulate with hydrochloric acid and divide into two parts. To one part add test solution of potassium ferrocyanid: A blue precipitate indicates ferric iron. To the other part add potassium ferrocyanid: A blue precipitate indicates ferrous iron. Step III.-Dissolve 2 grams of the original substance in 20 cc. of 10% solution of potassium hydroxid and boil; an odor of ammonia indicates the presence of ammonium. Whether ammonium is present or not, cool the solution and filter; examine the filtrate as directed in Step IV, and the precipitate as in Step V. Step IV.-The filtrate obtained in Step III should be clear and colorless and measure about 10 cc. Divide it into three portions of 2.5, 2.5 and 5 cc. respectively. (a) Slightly acidulate one of the smaller portions with acetic acid and add test solution of calcium chlorid: A precipitate occurs; the salt is probably a pyrophosphate. Confirm by (c). Filter and boil the filtrate (or the clear solution if no pre- cipitation has occurred): A white crystalline precipitate occurring after a few minutes indicates a citrate. (6) Slightly acidulate the second smaller portion with acetic acid and add an equal volume of alcohol: A white crystalline precipitate occurring after a few minutes indicates a tartrate. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 131 (c) To the remaining portion of (5 cc.) add 5 cc. of a 10% solution of ammonium chlorid, and then add, a few drops at a time, 1.5 cc. of a 10% solution of magnesium sulfate, agitat- ing after each addition: A white crystalline precipitate indicates a phosphate. Confirm as follows: Thoroughly wash the precipitate until the wash-water gives no cloudiness with silver-nitrate solu- tion, dissolve in dilute nitric acid, neutralize with ammonium hydroxid, acidify with acetic acid and add 5% solution of silver nitrate. If a phosphate is present, a canary-yellow precipitate appears. To the filtrate from the precipitate obtained by the addi- tion of ammonium chlorid and magnesium sulfate to (c), or to the clear liquid if no precipitate was produced, add a little acetic acid and heat to boiling: A white flocculent precipitate indicates a pyrophosphate. Confirm by the silver-nitrate test applied as above: A white precipitate appears if a pyrophosphate is present. Step V.-Wash the precipitate obtained in Step III. into a test-tube with about 15 cc. of chloroform, shake well for a few minutes, filter, and divide the filtrate into two portions (a) and (b). Heat both portions of the filtrate in porcelain capsules on a water-bath until the chloroform is all evaporated. (a) Add a small quantity of hot water slightly acidulated with sulfuric acid to the residue in one of the capsules, and filter. Divide the filtrate into three equal parts. 1. Add to one portion Mayer's reagent: A precipitate indicates an alkaloid. 2. Add to the second portion Labarraque's solution, using a quantity sufficient to destroy blue fluorescence if observed, and then a few drops of ammonium hydroxid: An emerald-green color indicates quinine. 3. To the third portion add ammonium hydroxid in slight excess, filter, reject the filtrate, dissolve the precipitate in about 1 cc. of water, containing a few drops of diluted acetic 132 QUALITATIVE CHEMICAL ANALYSIS. acid, neutralize exactly with potassium hydroxid, and add about 1 cc. of a saturated solution of Rochelle salt: A white precipitate indicates quinine or cinchonidine. Filter off the precipitate, dissolve in diluted hydrochloric acid, add potassium-hydroxid solution and 2 cc. of ether, and shake well. The quinine dissolves, while the cinchonidine remains as a crystalline precipitate at the line of separation of the two liquids. To the filtrate from the precipitate in 3, or the clear solu- tion if no precipitate was produced, add an excess of potassium hydroxid: A white precipitate insoluble in ether indicates cinchonine. (b) To the residue in the other capsule add a drop of sulfuric acid; into this put a fragment of potassium chromate, and after a few minutes draw this drop, by means of a glass rod, across the capsule: A beautiful violet color, changing quickly to yellow and red, indicates strychnine. Notes. As the foregoing scheme is intended partly for the benefit of students, I add some notes regarding the chem- istry involved in its construction. Step I.-When organic salts of the alkali metals are ignited, they leave their carbonates, which affect red litmus paper; the the qualitative reactions then separate the two. Step II.-This introduces the qualitative reaction for fer- rous and ferric iron. Step III.-This depends upon the fact that compounds containing ammonium give off ammonia when brought in con- tact with an alkali hydroxid. In addition, this step plays the role of precipitating the iron as a hydroxid, thus making it possible to operate with a colorless filtrate in Step IV. It then goes farther by rendering Step V assistance by precipi- tating the alkaloids and keeping them in the iron magma until the time arrives to proceed with their identification. The alka- loidal salts when treated with an alkali give up their acid and, being insoluble in the solution, they precipitate. Upon this QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 133 fact the process depends. It is easy to see that the alkaloids remain on the filter, while the acidulous radicals appear as potassium salts in the filtrate. Step IV.-The rationale of this step is simple. The object of adding acetic acid is to prevent the precipitation of calcium citrate in the cold. This is made necessary through the fact that pyrophosphates (most "iron pyrophosphates" are citro- pyrophosphates) produce with calcium-chlorid test solution a precipitate insoluble in acetic acid, whereas the citrate pre- cipitate is soluble.; if therefore acetic acid is first added, the citrate remains unaffected until the solution is boiled. There- fore if a precipitate forms in the cold, filter and test the filtrate as directed. Unless there be an excess, the citrate precipitate does not form in the cold, but calcium citrate, being insoluble in hot solution, precipitates when the solution is boiled. If the filtrate containing potassium hydroxid also contains a tartrate, the addition of acetic acid produces potassium acid tartrate which is practically insoluble in water, and totally insoluble in alcohol. Phosphates produce with magnesia mixture the white crystalline ammonio-magnesium phosphate and as pointed out by Nagelvoort (Am. Journ. Pharm., 1895, page 210) an excess of magnesia mixture is objectionable and apt to lead to erroneous conclusions. The magnesia mixture is prepared in the course of the process, acting upon the suggestion of Steiglitz (Am. Journ. Pharm., 1891, page 583), as follows: The filtrate con- taining potassium hydroxid has added to it ammonium-chlorid solution, whereupon, as shown in a previous reaction, ammonium hydroxid is generated. There remains, however, enough am- monium chlorid in the solution to prevent precipitation of mag- nesium hydroxid when the magnesium-sulfate solution is added. Having subjected the sample to the test and obtaining what gives every evidence of being a phosphate, the reaction -with silver nitrate acts in a confirmatory manner. Orthophosphates give with this reagent a yellow precipitate and pyrophosphates 134 QUALITATIVE CHEMICAL ANALYSIS. a white one. The separation of the pyrophosphate from the phosphates is made possible in this step as a result of the fact pointed out by Fresenius, that pyrophosphates produce with magnesium sulfate a precipitate of magnesium pyrophosphate soluble in excess of magnesium sulfate and not precipitated by ammonium hydroxid, which, being the contrary of the behavior of orthophosphates, serves to separate the two acids. The filtrate from the phosphate precipitate, or the solution in which the reagent has produced no effect, is then acidified with acetic acid and heated to boiling: a white flocculent precipitate in- dicates a pyrophosphate. Step V.-The fact upon which this step is based has been partly explained in Step III., where the alkaloids remained in the magma, and being soluble in chloroform, that solvent, after being thoroughly shaken with the residue, takes them 'up. By treating the residue with hot water containing a few drops of diluted sulfuric acid, the sulfates of the alkaloids are formed, and being more soluble in hot water than in cold, the process directs that condition. Mayer's reagent precipitates all the alkaloids included in the scheme, and if no reaction occurs, their absence is safely reported. The test for quinine is made with Labarraque's solution, and as this is a new method a word regarding it will not be amiss. Every one who has had occasion to qualitatively test for quinine with chlorine or bromin water must know the diffi- culties encountered through the inconvenience of obtaining either of the above two reagents in a condition to be depended upon. The Labarraque's solution is always at hand. The chemistry concerned in the reaction is easily understood: The Labarraque's solution coming into contact with the acid of the solution under examination has its chlorin liberated, which, if quinine is present, forms with it and a few drops of ammonia the characteristic thalleoquin-shown by an emerald- green-colored solution. Having in many qualitative quinine determinations applied the test as above directed, with the QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 135 most satisfactory results the writer has no hesitation in advo- cating its use in preference to the others referred to. It might be of interest to here mention that quinidine also gives a green color with this test, but as its higher price precludes any possibility of its ever being substituted for quinine, it is unnecessary to point out the method of differentiation. The cinchonidine reaction is dependent upon the fact that sodium and potassium tartrate (Rochelle salt) produces with it the insoluble cinchonidine tartrate. Quinine behaves in a similar manner towards this reagent, but the identification in solution 2 of this step eliminates that source of error. If necessary, the alkaloid can in the event of a doubt be further identified as directed. Cinchonine is identified by its behavior towards ether. Po- tassium hydroxid precipitates it; ether is added and the cin- chonine being insoluble, remains as a' white bulky precipitate. In another portion of the residue the strychnine is identified. The reaction is characteristic, and if applied as directed will detect minute quantities. The entire process is simple, accurate, inexpensive to operate, quickly carried out, and has everything to commend it. 94. A SCHEME FOR THE DETECTION OF POISONS. Divide the suspected sample into 3 parts, A, B, and C, and treat as follows: A. (1) If a liquid, place in a capsule, and on a water-bath evaporate to a syrupy consistency (2) If a solid, chop up or cut up with scissors into smallest possible pieces. (3) Transfer product of either (1 or 2), to a flask provided with a reflux (upright Liebig's) condenser or a long tube drawn through the cork of flask. Cover the sub- stance with twice its bulk of a 1% solution of tartaric 136 QUALITATIVE CHEMICAL ANALYSIS. acid in alcohol, and heat on a water-bath for one hour (Stas-Otto). (4) Remove from the water-bath, cool, filter, and carefully concentrate the filtrate on a water-bath until all the alcohol is dissipated. (5) Filter the concentrated extract through a wetted filter and again evaporate on water-bath to a syrupy consistency. (6) Dissolve the syrupy extract in absolute alcohol, stirring carefully to aid in effecting as complete a solution as possible. Filter once more, and again drive off the alcohol on the water-bath. (7) Dissolve the residue from (6) in distilled water, render alkaline with sodium hydroxid, pour into a separatory funnel, and extract it with ether, making at least two extractions. (8) Divide the ethereal extract from (7) into two portions, each contained in an evaporating dish, and allow the ether to volatilize spontaneously; the alkaloids, strych- nine, and veratrine should be tested for according to Chart 89, Steps 2 and 3, respectively, in one of the dishes, and in the other atropine and cocaine should be tested for according to Step 2. (9) The residue from the separatory funnel is poured into an evaporating dish, NH4OH added until ammoniacal, and placed on a water-bath, heating it until all the remaining ether is dissipated, and then set aside for 12 hours. (10) After 12 hours, warm the product of (9), pour into a separatory funnel, and extract it with amylic alcohol. The amylic alcohol extract is carefully evaporated in a porcelain capsule and morphine, identified as in Step 1, Chart 89. B. (1) Stir this portion prepared just as in A (1) and (2), with about 200 cc. of distilled water, and acidify (if QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 137 alkaline or neutral, not otherwise) with 1 or 2 cc. HCI (C. P.). (2) Place the solution prepared as in (1) on a dialyzer and float it in a liter of distilled water contained in a porcelain vessel. (3) After 24 hours, concentrate the water in the porcelain dish by evaporation on a water-bath. (This method separates from amorphous organic matter any crys- talloid substance, be it inorganic or organic.) (4) Divide the dialyzed extract (evaporated to about 50 cc- in (3)) into two equal portions. Test 1st portion for As, Hg, Sb, Zn, Pb, with H2S. Test 2d portion for Phenol, Chloral, Chloroform, Aniline,. Nitrobenzene, Hydrocyanic Acid, Acetanilide, Phe- nacetin and the mineral acids. C. (1) Prepare as in A ((1) and (2)); place in an evaporating dish, add an equal bulk of strong pure HCI, and warm on the water-bath, from time to time adding a crystal of KCCO3 and replacing water lost on evaporation. Con- tinue until all the organic matter is destroyed, expel chlorin by a higher heat, pass H2S in the warm solution, and test precipitate, according to the tables, for inor- ganic substances and the acids (except HCI). 95. A SCHEME FOR URANALYSIS. Observe: 1. Quantity passed in 24 hours. It should be from 1200; to 1500 cc. 2. Color and transparency.-Colorless, yellow to brown, clear, cloudy or opaque. 3. Reaction.-Acid, alkaline or amphoteric; normal urine is faintly acid. 4. Specific Gravity.-Should be 1.015 to 1.025 at 15° C. 138 QUALITATIVE CHEMICAL ANALYSIS. 5. Sediment-Note its quantity, and examine its character with a microscope. Notes: 1. When it is directed to warm the urine do not boil. 2. If not perfectly clear, the urine should be filtered before applying tests. If filtration does not clarify it, add a few cc. of NaOHsol., agitate, and filter; or shake a little talcum powder with the urine and filter. 3. If much albumin is present, it should be removed before testing for sugar. 4. Putrid urine should not be tested for sugar by any reagent containing copper or bismuth. 5. If the quantity of U (abbreviation used in this scheme for urine) is too small to float the urinometer, it may be diluted with an equal volume of water, and the last two figures of the specific gravity of this dilute durine, multiplied by two, or the specific gravity may be taken by a specific-gravity bottle. G. To calculate the quantity of total solids from the specific gravity, multiply the last two figures of the specific gravity by 2.33. This will give the number of grms. in 1000 cc. of urine. The last two figures also indicate approximately the number of grains in a fluid ounce. Full details regarding this relationship between the specific gravity and the amount of total solids may be found in Bartley's Clinical Chemistry. Organic Constituents (Abnormal): (1) Albumin. (a) Heat Test.-Add 10 drops of strong acetic acid to 10 cc. of U. Heat; cloudiness or precipitate, if any, indicates albumin. <b) Nitric-Acid Test.-Put 2 cc. of colorless HN03 into a test-tube, incline the tube, and add slowly, by means of a pipette, 4 cc. of U. sharp white band (zone) at point of contact indicates albumin. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 139 Precautions. 1. Mixed urates if present in excess will also give a band higher up. It is dissipated by warm- ing (not boiling). 2. After the administration of resinous drugs', (copaiba, etc.) or turpentine, a yellowish clouded zone also forms, which is redissolved by alcohol (albumin zone does not dissolve). (c) Picric-Acid Test.-Mix equal volumes of saturated solution of picric acid and U, shake and warm; any remaining ppt. is albumin. Precaution. Picric acid precipitates also urates, peptones, and vegetable alkaloids, which redissolve on warm- ing. (d) Tanret's Test.-Acidify 5 cc. of U with acetic acid, add Tanret's reagent drop by drop until 2 cc. have been added. Then warm. Any ppt. remaining is albumin. Precaution. Same as under (c). (c) Potassium-Ferrocyanid Test.-Acidify 4 cc. of If with acetic acid, add 2 cc. of a saturated soluti n of K4FeCye; any precipitate is albumin. (/) Quantitative Estimation.-Fill an Esbach albuminom- eter to the letter "U " with urine, and then to the letter "R" with Esbach's reagent. Cork securely, shake well, and set aside for 24 hours, agitating once or twice during that time-then read. Each one of the main divisions read off indicates 1 grm. of albumin in a liter of urine. (2) Peptones. (a) Ralfe's Test.-Place 4 cc. Fehling's reagent in a test-tube, and gently overlay with urine. At point of contact a zone of phosphates forms; above this 140 'QUALITATIVE CHEMICAL ANALYSIS. •another rose-colored zone, or "halo," will float if peptone is present. If mixed with albumin the halo will be purple. (6) Randolph's Test.-To 5 cc. of faintly acid urine add 4 drops of a saturated solution of KI and 4 drops of Millon's reagent. If peptones or bile acids are present, a yellow ppt. falls. Test for bile acids; if these be absent, the yellow ppt. indicates peptones. (3) Glucose (Sugar). (a) Fehling's Test.-Place 5 cc. of Fehling's reagent in a test-tube, dilute with 5 cc. water and heat to boiling. Add now drop by drop 5 cc. of urine, heating after each addition. A yellow or orange coloration or a brick-red ppt. of copper suboxid (CU2O) indicates glucose. (b) Pavy's Test.-Place 5 cc. of Pavy's reagent in a test- tube and warm. Now add 5 cc. of U; a partial or a total disappearance of the blue color indicates sugar. (c) Maine's Test.-Heat 5 cc. of Haine's reagent in a test-tube to boiling. Drop by drop add half a cc. of U, and boil again; any turbidity, or an orange-red ppt. of Cu2O, indicates glucose. ;(d) Bdttger's Bismuth Test.-Place in a test-tube 3 cc. of U, 1 cc. of solution of Na2CO3 and a little (0.3 grm.) bismuth subnitrate; boil these together for 2 minutes. If sugar be present in quantity, black metallic bismuth deposits; if a small quantity only is present the sol. will assume a grayish color. (e) Nylander's Test.-Boil together in a test-tube 10 cc. of U with 1 cc. of Nylander's reagent. If a light- gray or black precipitate forms it indicates glu- cose. (/) Indigo-Carmine Test.-Place 4 cc. of a freshly pre- pared solution of indigo carmine in a test-tube, add half of a cc. of Na2CO3 solution and boil together; the QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 141 color should persist; if it does not, add another cc. of the indigo-carmine solution (caustic alkalies discharge the color of indigo carmine). Add now 3 drops of U, and without agitation warm 1 minute. If glucose be present the color changes to purple, red and finally straw-yellow. Now shake the tube and the colors recur in the reverse order. 0) Quantitative Estimation (by Fermentation).-Take A part of a cake of Fleischmann's yeast, shake thor- oughly with 10 cc. urine, pour into an Einhorn sac- charometer, and set aside for 24 hours in a room of ordinary temperature (25° C. = 77° F.). Read off the percentage of glucose present. (A) Quantitative Estimation (with Fehling's Reagent).- Place in a 200-cc. flask 10 cc. of Fehling's solu- tion; to this add 10 cc. of a freshly prepared 10% solution of K4FeCy6 and 30 cc. of water. Heat the mixture on a water-bath (best temperature for the operation being between 80° and 90° C.); the U, diluted if it contains much sugar, is then run in drop by drop until the blue color just disappears. Excess of glucose added quickly turns the solution yellowish-brown (copper ferrocyanid forms). This is Prof. Bartley's method and is both reliable and rapid. (4) Indican (Uroxanthin). (a) Place 4 cc. of HC1 in a test-tube, add 3 drops IINO3, and agitating constantly add drop by drop 10 to 20 drops of urine. If indican is present in normal quantity, the solution will be colored delicate yel- lowish red; if in excess, the solution is colored red to violet. Precaution. If biliary acids are present, remove them before testing for indican by adding to 10 cc. of U 8 drops 142 QUALITATIVE CHEMICAL ANALYSIS. of Pb(6211302)2 solution and filtering. The filtrate is now tested for indican. (&) Place in a test-tube 4 cc. each HC1 and U, agitate, add 2 or 3 drops of dilute (1:3) solution of chlorinated soda, and shake; a reddish-blue or bluish-black colora- tion indicates indican (indigo is formed in this reaction ; a weak solution of NaClO is directed, as an excess would bleach the indigo). If now 2 cc. of CHCI3 be added and the mixture agitated, the indigo is dissolved out and with the chloroform settles at the bottom as a blue layer (the depth of the blue color is indicative of the quantity of indican present). (5) Blood. (a) Heller's Test.-To 5 cc. of U contained in a test-tube add 2 cc. of KOH solution and warm. The earthy phosphates which precipitate carry with them the blood coloring-matter, and if blood is present the precipitate will be blood-red, in ab- sence of blood, white. (6) Almen's Test.-Shake together in a test-tube 5 cc. each of tincture guaiacum and hydrogen dioxid (or old resinified turpentine oil), and drop by drop add about 5 cc. of U. Let stand a few minutes; if blood is present, a blue or bluish-green coloration is formed in the upper layer. If much blood is present, on agitating the tube it will diffuse through the entire liquid, giving it a creamy-bluish color. (6) Bile. (a) Heller's Test (for Bile Pigments).-Put 6 cc. of HC1 in a test-tube and drop in just enough of the U to color it. Underlay this mixture with pure HNO3. A play of colors at point of contact indicates biliary pigments. (&) Fleishl's Test.-Underlay a mixture of 5 cc. each strong HNO3 and U, with strong H2SO4. A play of QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 143 colors from rose to purple and green at point of con- tact indicates bile. (c) lodin Test.-Upon the surface of 5 cc. of U, carefully float 10 drops of tincture of iodin. At the point of contact an emerald-green zone is formed if bile is present. (d) Pettenkofer's Test (for Biliary Acids).-Add to 5 cc. U contained in a test-tube 4 drops of a solution of cane-sugar (saccharose 1:3), shake, and carefully underlay with strong H2SO4. Let stand for a few minutes; if biliary acids be present, a purple band is formed at point of contact. (e) Oliver's Peptone Test (for Biliary Acids).-Clarify the U by filtration, and dilute to the sp. gr. of 1.008. Place in a test-tube 4 cc. of Oliver's reagent and run into it 1 cc. of the U, diluted as above. If biliary acids are present, a distinct milkiness promptly appears, which becomes more intense after a few minutes. Oliver's reagent is composed of pulverized peptone, 2 grm.; salicylic acid, 0.25 grm.; acetic acid, 2 cc.; and sufficient distilled water to make 250 cc. Precaution. The above test is very delicate and reliable, but only in the absence of albumin, which should be removed by boiling the U with a few drops of HC2H3O2 and filtering. (7) Acetone. (a) Legal's Test.-Pour into a test-tube 2 cc. of a strong freshly prepared solution of sodium nitroprusside, and add 4 cc. of U and 2 cc. NaOH solution. The mixture acquires a red coloration, which may be due to creatinin (a normal constituent of U) as well as to acetone. Add 6 or 8 cc. of glacial HC2H3O2; if the mixture now assumes a claret-red or violet 144 QUALITATIVE CHEMICAL ANALYSIS. color, acetone is present in considerable quantity; if the color is discharged by the acid, it was due to creatinin only. (6) Lieben's Test.-Pour into a test-tube 6 cc. of U, add 10 drops solution of iodin and about 1 cc. of NH40H, and heat. If acetone be present, crystals of iodoform will form and deposit; the iodoform may be recognized by its characteristic aromatic odor. •Organic Constituents (Normal): (1) Urea (Carbamid, CH4N2O), Quantitative Estimation of. (a) Fill a Doremus ureometer to the double mark with hypobromite solution (made by dissolving 100 grm. of NaOII in 250 cc. of water, and to this adding 25 cc. of bromin), then add enough water to half fill the bulb. Now add 1 cc. of U by means of a nipple- pipette, forcing it as far up into the graduated cylinder as possible, stopper securely, let stand 15 minutes or until all the nitrogen is evolved, then read off. (6) Gas-tube Method of Bartley.-Pour into the gas-tube a 20% KBr solution up to the fifth division and chlorinated-soda solution to the twentieth division; the tube is now inclined, carefully overlayed with 5 cc. of distilled water, and 1 cc. of U carefully measured is added from a nipple-pipette, carefully avoiding its mixing with the reagents. The thumb of the right hand is now tightly pressed over the opening of the tube, which is firmly held in both hands and slowly inverted (carefully avoiding violent agitation) until reaction is complete (in from 2 to 4 minutes). Now invert the gas-tube, make a careful reading, and thus inverted open it under water contained in a broad, deep vessel and again read off. The difference between the first and second readings QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 145 equals the number of cc. of nitrogen evolved. Each cc. of N=0.0027 grm. of urea in 1 cc. of U. (2) Urohaematin, Hartley's Test.-Dilute the total U col- lected in 24 hours with distilled water till it measures 1.8 L; if the amount for 24 hours exceeds this figure, concentrate it to this quantity. Take 8 cc. of the so prepared U, add 2 cc. of pure strong HNO3, and let stand for some time. If urohaematin is present in normal quantities only, a slight change of color will be seen, but if present in excess, the liquid will become pink, red, crimson, or purple in color, according to the quantity present. (3) Vegetable Coloring Matter. (a) Observed in alkaline urines having a red or reddish- brown color. Add HC1: the urine will turn yellow. Add an excess of NH4OH: the urine again assumes a reddish color. (6) Test for Urobilin.-To 5 cc. of U add 2 cc. NH4OH: the urine will assume a greenish hue. Filter, to the filtrate add 2 cc. of a 1% solution of ZnCb, and shake. A rose-red color with greenish fluorescence is due to urobilin. (4) Uric Acid, C5Il4N4O3.( (a) Murexid Test.-Evaporate 10 cc. of U to dryness in a porcelain capsule, and then add a drop or two of HNO3 to dissolve the residue. Dissipate the uncom- bined HNO3 by heating on a water-bath. When dry, moisten the residue with 1 or 2 drops of NH4OH. A purple-red color of murexid indicates uric acid. Inorganic Constituents : (5) Chlorids.-Approximate Estimation. I (a) Add 2 drops of strong HNO3 to 5 cc. of U contained in a test-tube and mix well (HNO3 keeps phosphates in solution); add now 1 drop of a 1:8 solution of 146 QUALITATIVE CHEMICAL ANALYSIS. AgNO3. If the U contains 0.5% of chlorids, they will be ppd. as cheesy lumps, which do not further break up or render the urine more milky by moving the tube about. If the U contains 0.1% or less of chlorids, no cheesy lumps will appear, but a simple cloudiness is uniformly diffused through the entire liquid. Precaution. If much albumin be present in the U, it should be removed before applying above test. (b) Quantitative Estimation.-Dilute 10 cc. of U with 40 cc. of distilled water, add 10 drops of 10% potas- sium-chromate solution (free from chlorids), and from a burette run in drop by drop tenth normal AgNO3 solution, until a permanent reddish-brown color of silver chromate is produced, indicating end-reaction. N Each cc. - AgNO3 solution= 0.00584 grm. of chlorids, calculated to NaCl. (6) Phosphates (1. Earthy). (a) Add to 5 cc. of U 3 cc. of NH4OH; the earthy phosphates are precipitated. These may be separated by filtration, dried at a low heat, and weighed-if required. (b) (2. Alkaline). Approximate Estimation.-Filter out the earthy phosphates as precipitated in (a), and to the filtrate contained in a test-tube add | its own volume of magnesia mixture. If the entire fluid presents a cloudy appearance or a milkiness, the alkaline phosphates are normal. If, however, a de- cided, dense, milk, or cream-like precipitate forms, the alkaline phosphates are present in greater than normal quantities. If the fluid is but very slightly cloudy, transmit- QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 147 ting light, the phosphates are present in less than the normal quantities. (7) Sulfates.-These are usually reported as potassium indoxyl-sulfate (indican). An approximate method for the estimation of sulfates is the following: To 6 cc. of U contained in a test-tube add 8 drops of HC1; the mixture is shaken and 2 cc. of BaCB added. An opaque milky cloudiness indicates that the sulfates are present in normal quantity. If the opacity is intense, the whole mixture pre- senting a creamy appearance, the sulfates are present in excess above the normal quantity. If the cloudiness is so slight as to transmit light, the quantity of sulfates is subnormal. Microscopical Examination.-Besides the chemical examina- tion as given in the above scheme, a microscopic examination of the sediment should likewise be made. The more important constituents revealed in this way are the following: (a) Epithelium, whether single cells or squamous masses are present. (&) Crystals of uric acid, triple phosphates, calcium oxalate, cystin plates, etc. (c) Amorphous deposits of urates, broken-up cellular structures, detritus, etc. (d) Blood, discs and casts. (e) Pus, single cells and sacs. (/) Casts (tube, waxy, hyaline, granular, epithelial, etc.) (g) Mucous, cells and casts. Also, Fungi, Bacteria, and Spermatozoids are sometimes reported. 148 QUALITATIVE CHEMICAL ANALYSIS Report.-The findings of a urinalysis may be reported according to the following scheme used by the authors: New York, 190. REPORT ON URANALYSIS. When Received Dr Patient...................... » Physical Examination. Odor Color Spec. Gravity Reaction Appearance Sediment Quantity passed in 24 hours Chemical Analysis. Albumin Sugar Urea Bile Acetone Indican Chlorids Phosphates Microscopical Examination, Epithelium Crystals Amorphous Deposits Blood Pus Casts Mucous Fungi Spermatozoa Bacteria Analyst. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 149 PREPARATION OF REAGENTS. Reagents should be prepared only from chemically pure substances, or, better, such as are guaranteed as to their purity and strength, e.g., "Merck's Guaranteed Reagents." The success of the analytic operations depends very largely on the purity of reagents. The water used in the preparation of reagents should be freshly distilled and tested for impurities. ACIDS. When "acids" are mentioned in the text, dilute acids are meant unless otherwise specified. When "strong" or "concentrated" acids are mentioned use the undiluted acids of the strength specified by the U. S: P.- HC1, 1 part to 4 parts H2O by volume. H2SO4, 1 11 "4 " H2O " HNO3, 1 " "5 " H2O " Aqua Regia HNO3, 1 " "3 " HC1 " SALTS. Parts by Volume. (NH4)2CO3, 1 part to 8 parts H2O, add 1 part NH4OH. (NH4)2C2O4, 1 " "24 " H2O NH4C1, 1 " "10 " H2O KOH, 1 " " 10 " H2O NaOH, 1 " "10 " H2O K2CrO4, 1 " "10 " H2O K2Cr2O7, 1 " "10 " H2O K3FeCy6, 1 " "15 " H2O K4FeCv6, 1 " "15 " H2O 150 QUALITATIVE CHEMICAL ANALYSIS. Na2CO3, 1 part to 10 parts H2O Na2HPO4, 1 11 "10 " H2O BaCl2, 1 ' " 10 " H2O HgCl2, 1 " "20 " H2O AgN03, 1 " "20 " H2O Pb(C2H3O2)2, 1 " "10 " H2O MgSO4, 1 " " 8 " H2O Co(NO3)2, 1" "10 " H2O (NH4)MoO4, 1" " 4 " NH4OH(strong),add 15parts HNO3(34%) KCy, 1 " " 10 " H2O KI, 1 " " 25 " H2O FeSO4, 2 " "10 " add H2S04 a few drops. (NH4)2SO4, 1 " "10 " H2O H2C4H4O6, 1 " "20 " H2O Ba(0H)2, 1 " " 20 " H2O BaSO4, a saturated solution. CaSO4, NaHC4H4O6; " GASES. H2S.-Generate the gas from FeS by a dilute H2SO4 (1 p. acid to 12 p. water). NH4HS.-Pass H2S in a slow current into some pure NH40H until the latter is saturated. This solution is some- times called yellow ammonium sulfid. (NH4)2S solution is made by mixing 3 parts of the fore- going with 2 parts of ammonia-water. °PECIAL REAGENTS. Fe2Cl6.-1 part to 10 parts H2O by volume. KSCy.-1 " " 10 " " " NaC2H3O2.-A saturated -solution. QUALITATIVE ANALYSIS OF ORGANIC SUBSTANCES. 151 NaC102-Mix 3 grm. of bleaching-powder (chlorinated lime) with 3 grin, of Na2COa (anhydrous) and dissolve in 400 cc. of distilled water. Let settle, and decant the solution. Bromin-water.-Add some Br to water, agitate, allow to stand and decant for use. Ether.-U. S. P. ether. Alcohol.-U. S. P. alcohol 95%. Copper sulfate.-1 part to 10 parts H2O. Tannic acid.- 1 part to 100 parts H2O. Dimethyl-amido-azo-benzene.-1 grm. to 200 cc. C2H50H. Indigo-carmine.-10% solution. Alphanaphthol.-15 parts to 100 parts C2H50H. Picric Acid.-A saturated solution in water. Magnesia Mixture.-1 part MgSO4 cryst., 2 parts NH4C1, 4 parts NH40H, 8 parts H2O. Nessler's Reagent.-(1) Dissolve 35.0 grm. KI in 100 cc. H2O. (2) Dissolve 17.0 grm. HgCl2 in 300 cc. H2O. The liquids may be heated to aid solution, but if so, they must be cooled before mixing. Pour the second solution into the first until a permanent ppt. is produced, then dilute with 20% NaOH solution to 1000 cc.; agitate and again add enough of solution (2) until a permanent ppt. forms. Allow to stand till settled, and decant the clear portion for use. Millon's Reagent.-1 p. metallic Hg by weight, and 2 p. HNO3 (strong) by weight; gently warm until all Hg dissolves, and dilute with 6 p. H2O. Nylander's Reagent.-4 grm. Rochelle salt, 2 grm. BiONOa, a 10 grm. NaOH (dissolved in 90 cc. water). Mix, and keep in a dark bottle in the dark. Gunzberg's Reagent.-1 grm. vanillin, 2 grm. phloro- glucin, and 100 cc. alcohol. 152 QUALITATIVE CHEMICAL ANALYSIS. Froehde's (or Frohde's) Reagent.-1 grm. sodium molyb- date 10 cc. H2SO4 (strong). Fusing Mixture.-1 p. Na2COs and 3 p. KNO3. Iodin Solution.-1 grm. I, 2 grm. KI, and 300 cc. H2O. Esbach's Reagent.-10 grm. picric acid, 20 grm. citric acid, and water to make 1000 cc. of finished product. Fehling's Reagent.-(1) 34.64 grm. CuSO4 (crystal). Dissolve in water and make up to 500 cc. (2) 173 grm. Rochelle salt, and 125 grm. NaOH. Dissolve in water and make up to 500 cc. The solutions are to be kept separately, and mixed together in equal quantities just before use. Diazo Reagent.-(1) 2 grm. sulfanilic acid, 50 cc. HC1 (strong) and H2O to make 1000 cc. of finished product. (2) 5 grm. NaNO2. Make up to 1000 cc. with water. Dragendorff's Reagent.-1.5 grm. BiONO3, boil with 20 cc. H2O, add 7 grm. KI, shake, and add 20 drops HC1 (dilute). Mayer's Reagent.-1.35 grm. HgCh, dissolved in 50 cc. water; then add 5 grm. KI dissolved in 50 cc. H2O, and mix the two solutions. Haine's Sugar Test.-2 grm. CuSO4, dissolve in 15 cc. H2O, add 15 cc. glycerin, mix well, and add 150 cc. solution KOH (U. S. P., 1890). Tanret's Reagent.-(1) 1.35 grm. HgCl2, dissolved in 30 cc. H2O (hot). (2) 3.32 grm. KI, dissolved in 30 cc. H2O. Mix the solutions 1 and 2, add 20 cc. acetic acid, and make up to 100 cc. with H2O. " Euchlorin."-Place in a test-tube 0.2 grm. of KCIO3, add to it 4 drops HC1 (strong), and when Cl gas is evolved dilute with H2O to 30 cc. INDEX. Acetaldehyde, 108 Acetanilid, 99, 115 Acetate, 70, 72, 75, 83 Acetphenetidin, 100 Acid-barium group, 76 Acid, benzoic, 96 " defined, 12 " picric, 99 Acid-sulfid group of metals, 40 Acids and acidulous radicals, 69 " detection of, in insoluble sub- stances, 75 " detection of, in solution, 70 11 names of, 13 " preliminary examination of, 69 " special tests for Group I. 76 " " " " " II, 76 " " " " " III, 79 " table of, 10 .Aconitine, 92 Adhesion, 5 Alcohol, amylic, 111 " ethyl, 104 " grain, 104 " methyl, 104 Alcohols, 126 Aldehydes, 127 Alkali-sulfid group of metals. 50 Al men's test, 142 Alloys and hard metals, 67 Aloin, 95. Aluminum, 54 Ammonium, 63 Amyl nitrite, 111 Amylic alcohol, 111 Analysis, systematic, 22 Antimony, 45 Antipyrine, 99-115 Apomorphine, 92 Aristol, 90 Arsenate, 74-78 Arsenic, 42 Arsenite, 74, 78 Arsenous, 43 Atoms, 2 Atropine, 93 Barium, 57 Bartley's scheme for identification of organic compounds, 116 Bartley's urea method, 144 Bases defined, 12 Benzaldehyde, 111 Benzene, 110 Benzin, 110 Benzoate, 72, 75, 84, 96 Benzoic acid, 96 " aldehyde, 111 Benzol, 110 Benzosulphinid, 100 Betanaphthol, 102 Bicarbonate, 72 " and carbonate, 82 Bismuth, 41 Bonds, 5 Borate, 74, 75, 77 Borax heads, 65 Bbttger's test, 140 Bromate. 70, 80, 81 Bromid, 73, 79, 81 Brucine. 92 Butyl chloral, 96 Cadmium, 44 Caffeine, 93 153 154 INDEX Calcium, 59 Camphor, 97 " monobromate, 102 Cane-sugar, 98 Carbohydrates, 128 ' ' scheme for identifi- cation of, 91 Carbolate, 72, 75, 86 Carbolic acid, 111 Carbon, 87 Carbonate group of metals, 57 Carbonates, 70, 72, 77 " and bicarbonates, 82 Charcoal test, 26 Chart for acids, 69 " " insoluble phosphates, 64 " " identification of metals, 28 " " separation of Group I metals. 30 " " separation of Group II metals, 34 " " separation of Group III metals, 47 " " separation of Group IV metals, 56 Chemical change, 3 Chemism, 4 Chemistry defined, 3 Chloral, 96 Chloralamid, 101 Chloralformamid, 101 Chlorates, 70, 81 Chlorate, bromate, and iodate, 81 Chlorid, 70, 73, 79, 81 " group of metals, 32 Chlorin, 87 Chloroform, 110 Chromates, 70, 74, 78 Chromium, 55 Cinchona alkaloids, 93 Cinchonidine, 93, 94 Cinchonine, 93, 94 Citrate, 73, 83 Cobalt, 52 Cocaine, 93 Codeine, 92 Cohesion, 5 Compounds defined, 2, 3 Copper, 41 Creosote, 112 Cyanates, 81 Cyauids, 70, 72, 73, 80 Dextrine, 98 Diazo reagent, 152 Dichromate, 74 Dragendorff's reagent, 152 Elaterin, 95 Elements, 2 Equations, 11 Esbach's reagent, 152 Esters, 127 Ether, 109 Ether, acetic, 110 Ethers, 127 Ethyl, acetate, 110 " alcohol, 104 " carbamate, 100 " oxid, 109 Euchlor, 152 Exalgine, 115 Fehling's solution, behavior of or- ganic substances with, 90 Fehling's tests, 90, 140, 152 Ferric salts, 50 Ferricyanids, 70, 72, 73, 75, 82 Ferroeyanids, 70, 72, 73, 75, 82 Ferrous salts, 51 Flame tests, 60 Fleishl's test, 143 Fleitmann's test, 44 Formalin, 109 Formaldehyde, 109 Formate, 74, 75, 84 Formic aldehyde, 109 Frohde's reagent, 152 Fusel-oil. Ill Fusing mixture, 152 Gallate, 75, 85 Gallol, 85 Glusidum, 100 Glycerin, 112 Glycerol, 112 Grain alcohol, 104 Grape-sugar, 98 Groups, separation of, 20 Guaiac, 99 Guaiacol, 103 " carbonate, 102 Gums, 98 Gunzberg's reagent, 151 Haines' test, 140, 152 Hartley's test, 145 INDEX. 155 Heat test, 24 Heller's test, 142 Hydrocarbons, 126 Hydrochloric acid test, 27 Hydrofluorsilicate, 76 Hydrogen, 87 Hypochlorite, 70, 79 Hypophosphite, 74, 82 Immiscible solvents, behavior of or- ganic substances with, 88 Iodate, 70, 78, 81 lodid, 73, 80, 81 Iodoform, 96 Iodol, 96 Iron, 50, 51 Ketones, 127 Lactate, 85 Lead, 32 Legal's test, 143 Lieben's test, 144 Lithium, 62 Magnesium, 61 Manganese, 54 Marsh's test, 43 Mass, 2 Matter defined, 1 " theory of, 1 Mayer's reagent, 151 Mechanical mixture, 4 Meconates, 85 Menthol, 97 Mercuric salts, 40 Mercurous salts, 34 Metals, classified, 7 Metaphosphates, 74 Methyl alcohol, 104 " " detection of, in bev- erages, etc., 105 Milk sugar, 98 Miller's test, 107 Millon's reagent, 151 Molecules, 2 Molybdates, 85 Morphine, 92 Murexid test, 145 Naphthalene, 100 Naphthol, 102 Nessler's reagent, 151 Neutral barium group, 76 Nickel, 52 Nitrate, 70, 75, 81 Nitrite, 70, 75, 79 Nitrobenzene, 141 Nitrogen, 87 Nitrogen bases, 126 Nomenclature, 8 Non-metals, 7 Notation, 7 Nylander's reagent, 151 Nylander's test, 140 Oil of mirbane, 114 Oleates, 97 Oliver's test, 143 Organic acids, 126 ' ' compounds, detection of, 87, 91 " substances, behavior of, with Fehling's, 90 " substances, behavior of, with immiscible solvents, 88 " substances, Bartley's scheme for identification of, 116 Oxalates, 70, 73, 75, 77 Ox-gall, 97 Paraldehyde, 109 Pavy's test, 140 Perchlorates, 82 Pettenkofer's test, 143 Petroleum ether, 110 Phenacetine, 100, 115 Phenacoll hydrochlorid, 115 Phenazonum, 99 Phenic acid, 111 Phenol, 95, 111 Phenolate, 86, 95 Phenolsulphonate, 95 Phenylsalicylate, 102 Phosphates, 74, 76 chart for insoluble, 64 Phosphites, 74 Phosphorus, 88 Physical change, 3 Physostigmine, 92 Picric acid, 99 Poisons, detection of, 135 Potassium, 61 Preparation of solution for analysis, 65 Prescott's test for methyl alcohol in beverages, 106 Pyrogallates, 75, 85 156 INDEX Pyrogallol, 85 Pyrophosphates, 74 Qualitative analysis, 17 Quantivalence, 5 Quinidine, 93, 94, 115 Quinine, 93, 94 Ralfe's test, 140 Randolph's test, 140 Reagents, 18, 149 Resins, 99 Resorcin, 101, 115 Resorcinol, 101 " test for methyl alcohol in beverages, etc., 106 Rimini test, 106 Saccharin, 100 Salicin, 95 Salicylates, 75, 84 Salol' 102, 115 Salts, defined, 12 " . names of, 14 Santonin, 95 Scale compounds, identification of, 129 Separation of groups, 20 Sieker's test, 108 Silicates, 78 Silver, 33 Soap, 97 Sodium, 62 " carbonate test, 26 Solubilities, table of, 68 Stannic salts, 46 Stannous salts, 46 Starches, 98 Stearates, 97 Strontium, 58 Strychnine, 93 Succinates, 75 Sugar, cane, 98 " , grape, 98 " , milk, 98 Sulfates, 72, 76 Sulfids, 70, 72, 74, 75, 79 Sulfites, 70, 72, 74, 75, 77 Sulfocyanate, 73, 75, 82 Sulfur, 88 Sulfuric acid test, 25 Sulfonphenolates, 95 Sulfonal, 101 Sulfomethane, 101 Sulfonethylmethane, 102, 115 Symbols, 7, 10 Systematic analysis, 22 Table for identification of acetanilid, etc., 115 Table for identification of metals, 28 " " metals of Group 1, 30 " " " " " II, 34 " " " " " III, 47 " " " IV, 56 " " phosphates, 64 Table of acids, 10 " " metals, 9 " " non-metals, 8 " " solubilities, 68 Tannates, 75, 85 Tannin, 85 Tanret's test, 139, 152 Tartrates, 70, 73, 74, 83 Terpin hydrate, 103 Test, charcoal, 26 " , heat, 24 " , hydrochloric acid, 27 " , sodium carbonate, 26 " , sulfuric acid, 25 Thiosulphate, 70, 72, 74, 75, 78 Thymol, 97 Tin, 46 Trional, 101 Ultimate qualitative analysis, 87,119 Uranalysis, 137 Urethane, 100 Valence, 5 Valerate, 85 Valerianate, 85 Veratrine, 93 Zinc, 53