RECENT BOOKS QUALITATIVE ANALYSIS. 3 . S. Long. Ch.E., MS.. Ph.D., Professor of Inorganic Chemistry; H. V. Anderson. B.Ch.E., M.S., Associate Professor of Chemistry; T. H . Hazlehurst, Jr., A.B.. Ph.D.. Assistant Professor of Chemistrv.. all of Lehieh University. Revised Edition. Prentice-Hall, Inc., New York City, 1933. xv 266 pp. 5 Figs., 14 Tables. 14 X 20 cm. $2.25. This is a revision of the text published seven years ago under the authorship of Long, Chamberlin, and Anderson. [For review, see J. CHEM.EDUC.,6, 2309--10 (Dec., 1929).] "The six yean during which this book has been in use, have given opportunity for a fair trial of the tent. Several omissions have come to light, and the necessity for a more extended treatment of certain points has become clear.. . . The new material added during the present revision includes sections on Molar and Normal Solutions, Colloids, and Amphaterism. The Analysis of Anions has been greatly enlarged." A foundation of principles is laid down in the first three chapters under the titles: Ionization, Oxidation and Reduction, and Reversible Reactions. Further principles and the applications of them are brought out in connection with the analyses of the various groaps. Many numerical data are given, including ionization constants, solubility products, and the degrees of ionization of solutions of many compounds. Much of this is usually left for the course in quantitative analysis. I t would appear that a class should spend several hours on these first chapters before beginning the laboratory work. For the most part the principles are clearly and satisfactorily discussed. However, the definition of equivalent weight (p. 9). as the molar weight divided by the total positive valence, seems unfortunate. The term "equivalent weight" appears to mean "pram equivalent weight." Following a table of the solubility products of the sulfides of groups I1 and 111, there appears the sentence (p. 125) "According t o the table of Solubility Products, zinc is the element most likely t o he partially precipitated with Group I1 sulfides if (S?) is too high." This is really not a t all obvious from the table. The peculiar action of cobalt sulfide is, however, mentioned in the preface. After explaining the separation of NiS and CoS from the other sulfides of group 111 as resulting from the dow reaction between there and dilute HCI, the authors refer to "the less soluble CoS and N i S ' ( p . 149). I n the revision the authors have adopted the system of designating the valence of polyvalent ions by a number following the sign of the charge, as POlia, etc. I t seems t o the reviewer that there is a chance far the student t o he confused between this and an exponent, as in the case of the solubility product of hydrogen sulfide which is written (H+)%X W 2 ) = 1.1 X Perhaps SZ- would be clearer. The cations are divided into the five usual groups, the HC1 group being discussed first. Under each there are well-planned preliminary experiments, with emphasis directed to the principles involved. A brief summary of "commercial uses" of each element or ion is included. A detailed deswiption of the separations within each group is fallowed by an outline of the analysis of it and by numerous questions on procedure and principles. The student is left t o make his own outline for groups IV and V. Silver is confirmed by the addition of an iodide or bromide to the ammoniacal solution. The only test for cobalt is the borax-head test, and the cobaltinitrite test for potassium is not included. The anions are arranged in four groups, one more than in the original edition. The new one includes those acids whose silver salts are insoluble in water, hut soluble in nitric acid, and whose barium salts are soluble in water. A subdivision is made within the silver nitrate group on the basis of the insolubility of certain nickel salts in acetic acid. The book deserves consideration for adoption in courses in which there is time enough for the study of the principles and far the performance of the laboratory experiments outlined in it. The wealth of numerical data and applications should
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appeal to and be stimulating to all teachers of qualitative (and of quantitative) analysis. I t can well be recommended to the more serious-minded students for supplementary reading in connection with anv course in analvsis. LYMANE. PORTER
QUALITATIVE CAEMICAL ANALYSIS. Roy K. McAlPin~,Ph.D.. and Byron A. Sodc. Sc.D., University of Michigan. Based upon the tent of Albert B. Prescott and 0. C. Johnson. D. Van Nostrand Co., Inc., New York City, 1933. xii f 697 pp. 2 Figs. 15 X 23 cm. $*.50. I n 1864, Silas H. Douglas, professor of chemical technology and metallurgy a t the University of Michigan, published some "Tables for Qualitative Analysis" to be used by students in the labaratory in conjunction with the larger "Manual of Qualitative Analysis" by Fresenius. These tables and laboratory notes were used for ten years a t Michigan and three editions were published. I n 1873 the notes were enlarged t o an extent such that students were no Longer compelled to buy the Fresenius book which was and is still regarded as authoritative. The new edition bore the names of S. H. Douglas and A. B. Prescott. the latter being professor of organic chemistry and pharmacy a t the same institution. In the third edition of the DouglasPrescott book, a section on "Oxidation and Reduction" was contributed by Otis C. Johnson, a younger instructor a t Michigan. I n this section, first printed in 1886, one reads that just "as chemism acts between unlike particles-positive and negative factors-so bonds are stated as either positive or negative bonds" and the b w k was probably the fizst in which the attempt was made to teach students to balance equations of oxidation and reduction by counting the change in valence as a measure of the oxidizing or reducing power. Johnson was careful t o distinguish between the nitrogen in ammonia with what he cslled three negative bonds and the nitrogen of nitrous acid with its three positive bonds. This idea proved popular and the idea of the electron, which was introduced much later into chemical literature, was similar to what Johnson had in mind prior t o 1886, when he spoke of the negative bond. Since 1901, the book was published under the authorship of Prescott and Johnson whose names still appear on the cover and title of this new and excellent revision of Roy K. McAlpine and Byron A. Soule of the University of Michigan. The last previous edition appeared in 1917 and was edited by John C. Olsen of the Brooklyn Polytechnic Institute. The arrangement of the text has been kept the same, as far as possible, and instruction in the art of balancing equations of oxidation is given on pages 636-56 about where i t was put in 1886. Moreover, the scheme for analysis is substantially the same as that of the Fresenius book upon which Douglas based his Tables of 1864. To be sure, a number of distinct improvements have been introduced and the explanations are more adequate, but although some reactions are used which were unknown in 1864 there has been no radical Change. In fact the new editors feel that the student has less time t o devote to Laboratory practice today than formerly and "must depend less on the results of his own varied experimentation than on the discussions in class and on the notes which accompany the directions" and "although the laboratory method is undoubtedly the most interesting way of acquiring chemical knowledge, i t is essentially timeconsuming" so that "it is becoming general practice to cover in the laboratory only such typical situations as will serve to illustrate the material of the course." Rather than spend a lot of time in the laboratory acquiring analytical technic he is advised t o "browse through the book" and read some of the supplementary literature. The f i s t 148 pages of text have nothing whatever t o do with the details of analytical procedure. About 50 of these pages are
