Textbook of Quantitative Analysis

Abstract

This book has now been in constant use at the Massachusetts Institute of Technology for ten years in the author's classes and many of the changes made were suggested by contacts with the students. Professor H. W. Rogers has also examined the manuscript and kindly suggested some changes: A schedule of the work usually carried out by the students has been added which should be helpful to new users of the book. Under Acidimetry the table of acid-base indicators has been revised and an attempt made to bring the theory of the color change upi to date. Bronsted's theory of acids and bases is discussed and applications of the theory illustrated, although the text as a whole is not written in terms of the theory, for which reasons are given. Under Oxidation and Reduction an explanation of the theory of oxidation-reduction indicators is given and their use is illustrated. Under Gravimetric Analysis the discussion of colloidal solutions, aging of precipitates, coprecipitation, and post precipitation has been introduced. In Part I, the number of problems has been increased by about twenty per cent. Some new illustrations and some new procedures have been added. A few of the older procedures have been dropped as well as some of the old illustrations. In Part II of the book there have been numerous improvements, and under Steel Analysis an attempt has been made to describe well-known methods as carried out today by the chemists of the U. S. Steel Corporation or of the National Bureau of Standards. Under electrometric methods of analysis, some of the details in manipulation are omitted because numerous forms of apparatus are now on sale and the makers of the various instruments supply full directions for their use. The theory of the glass electrode, however, is discussed briefly. With respect to electrode potentials, the values are now given in terms of oxidation potentials, rather than reduction potentials, which means that all the signs are changed in the mathematical expressions. Considerable unnecessary confusion has resulted from the fact that in the United States many of our best physical chemists prefer to call an electrode potential positive which chemists of other countries and all physicists call negative. When the chemist says that the positive-tovi PREFACE negative direction in a Bunsen cell is from the zinc to the copper he is thinking of the current passing through solution, and when the physicist ^*^says that copper is positive to zinc in the Bunsen cell he is thinking of the current passing through the wire. Both are right, but when students are studying chemistry and physics at the same time it is less confusing when the chemist and the physicist both regard phenomena from the same viewpoint and use the same signs in their mathematical expressions. Moreover, all English books and the majority of the best books printed in the United States on analytical chemistry have now conformed to the nomenclature established by the physicists. WILLIAM T . HALL