RECENT BOOKS QUALITATIVB ANALYSISAND CHEMICAL EQUILIBRIUM.T. R. Hogness, Associate Professor of Physical Chemistry, University of Chicago, and Warren C Johnson, Associate Professor of Chemistry, University of Chicago. Henry Holt and Co., New York City, 1937. xii 417 pp. 27 figs. 23 X 14 cm. $2.75.
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Among the several recent attempts a t presenting the subject of qualitative analysis as a typical application of the principles of theoretical or physical chemistry, this text distinguishes itself by a number of commendable features. Half of the book is devoted to an elementary but clear and detailed discussion of those portions of physical chemistry which are directly illustrated by, and applied in, qualitative analysis (properties of solids, liquids and solutionsleaction velocity and chemical equilibrium-weak acids and bases-solubility product--collaids hydrolysi~complex ionsamphoteric suhstances-oxidation and reduction). Teachers of qualitative analysis will be surprised a t the enormous amount of information of the kind usually imparted by word of mouth only which is contained in this text. Answers are provided for most questions, even the most naive ones, with which teachers of the subject are always faced. The numerous problems worked out with unusual wealth of detail a t the end of each chapter, and the appendix on mathematics1 operations contribute to make the book an efficient educational tool. The theory of the solubility product as given by the authors is particularly satisfactory, although, even in an elementary text, salt effects on solubilities and on ionization constants should not be omitted. The presentation of the subject of oxidationreduction by means of equilibrium constants of half-reactions instead of single-electrode potentials is a distinct pedagogical advance. I t is to be regretted, however, that a short discussion of these potentials has not been included, and that the connection between the arbitrary choice of equilibrium constant for the half-reaction H2-2H+ and the arbitrary choice of zero potential far the normal hydrogen electrode is not mentioned. I n spite of their opinion to the contrary, we feel that the authors could have added considerable strength to their hook by including the, after all, so simple theory of acids and bases initiated by Brdnsted. 'l'hr rrprrimentnl portion uf the bo+k also contains appreciably n w r c informntion than mo.1 rlrmvntary texts of lhis kind. Thc method of nnolysir in\~olverthr urc
