Chicago, September, 1911.

CONTENTS

[PART I]
FUNDAMENTAL PRINCIPLES
CHAPTERPAGE
[I.]Introduction3
[II.]Osmotic Pressure and the Theory of Solution, I8
[III.]Osmotic Pressure and the Theory of Solution, II21
[IV.]The Theory of Ionization: Ionization and Electrical Conductivity33
[V.] The Theory of Ionization, II: Ionization and Osmotic Pressure; Ionization and Chemical Activity67
[VI.]Chemical Equilibrium. The Law of Mass Action90
[VII.]Physical or Heterogeneous Equilibrium.—The Colloidal Condition118
[VIII.]Simultaneous Chemical and Physical Equilibrium.—The Solubility- or Ion-Product139
[PART II]
SYSTEMATIC ANALYSIS AND THE
APPLICATION OF FUNDAMENTAL PRINCIPLES
[IX.]Systematic Analysis for the Common Metal Ions. The Ions of the Alkalies and of the Alkaline Earths. Order of Precipitation of Difficultly Soluble Salts with a Common Ion157
[X.]Aluminium; Amphoteric Hydroxides; Hydrolysis of Salts. The Aluminium and Zinc Groups171
[XI.]The Copper and Silver Groups. Precipitation with Hydrogen Sulphide199
[XII.]The Copper and Silver Groups (Continued). The Theory of Complex Ions216
[XIII.]The Arsenic Group. Sulpho-acids and Sulpho-salts242
[XIV.]Oxidation and Reduction Reactions, I251
[XV.]Oxidation and Reduction, II. Oxidation by Oxygen, Permanganates, etc.; Oxidation of Organic Compounds277
[XVI.]Systematic Analysis for Acid Ions299

LIST OF REFERENCES AND THEIR ABBREVIATIONS

Note.—(Stud.) affixed to a reference indicates that the original article is recommended as suitable reading for college students taking their second year of work in chemistry.

QUALITATIVE CHEMICAL ANALYSIS PART I FUNDAMENTAL PRINCIPLES

CHAPTER I INTRODUCTION

Qualitative chemical analysis is concerned with the determination of the kinds of matter present in any given substance. In its broadest sense it includes the determination of all kinds of matter, the elements, rare as well as common, and all their combinations, organic compounds as well as inorganic. The recognition of the presence of rare elements, such as radium, uranium, thorium, tungsten, cerium, etc., is becoming a matter of growing importance with the modern development of the subject of radioactivity and the technical exploitation of the rarer elements, and it is a common experience for an analytical chemist to be called upon to determine the presence or absence of alcohol in beverages, of formalin in milk or other foods, and not a rare experience to be obliged to make tests for the presence of alkaloids like strychnine, morphine, cocaine, or for the presence of numerous other organic compounds. In this book, however, we shall limit our material to the more common elements and their most important inorganic combinations, including only a few typical organic acids. The limitation of our experimental material will make it possible to devote special attention to the scientific principles underlying analysis, to secure a clear and definite grasp of them, and to impart with simple material such experience in the technique and methods of analysis as will train the student to apply both his theoretical and practical knowledge to any field of analysis occasion may require. Accurate qualitative analysis, [p004] in any field, will depend on the care taken in mastering the theoretical significance and the technique of the methods recommended for the specific problem before the analyst; the details of the methods themselves, in any problem involving more than elementary analysis, are sought and found by him as a matter of practice in suitable larger works, in monographs and in the original literature. With the object of suggesting this broader application of the training acquired and of cultivating the invaluable habit of the professional chemist of consulting larger works and the literature, frequent reference will be made to such larger works, and to original papers in which more special subjects of analysis or theory are elaborately treated.

To recognize, in a substance, the presence of any element or compound, one must know its characteristic reactions, which will make it possible to distinguish it from all other elements or compounds. Further, in order to reach conclusions with the greatest possible speed, directness, and conclusiveness, it is usually best to carry out an examination in some systematic way, rather than in a haphazard and irregular fashion. We distinguish, accordingly, two parts in our laboratory work: first, the study of characteristic tests or reactions of the common elements and such of their compounds as are of importance in elementary analysis (Part III), and, secondly, practice in a systematic method of analysis (Part IV). In the study of the reactions, the way will be paved for systematic analysis, by taking the elements in the groups, which form the basis of the system of analysis employed, and by analyses of mixtures of the elements of a group immediately after the group has been studied.