Complexometric Titrations (Schwarzenbach, Gerold) - Journal of

Journal of Chemical Education. Novick. 1997 74 (12), p 1463. Abstract: Complexometric titrations with EDTA have traditionally been performed in underg...
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COMPLEXOMETRIC TITRATIONS

Gerold Schwareenbach, Professor of Chemistry, University of Zurich. Translated by H a r r y Irving, University of Oxford. Interscience Publishers, Inc., New York, 1957. xviii 132 pp. 41 figs. 7 tables. 14.5 X 22 em. $3.75.

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O R ~ I N A L L Ypubli~hed by Ferdinand Enke Verlag, Stuttgart, in 1955 under the title Die ieomplezometrische Titmtion, the German edition of this book received immediate and widespread aacceptanoe, as shown by the fact that the first edition was sold out six months after its first aooear-

lator far any research monograph than the two distinguished scientists who have contributed to this volume. Professor Sehwar~enbach,in 1945, first pointed out the exceptional properties of aminopolycarboxylie acids in forming complexes of simple composition and great stability with a wide variety of metal ions. His later discovery, in 1949, of the first metal ion indicator, andogous to the familiar acidhase indicators for hydrogen ion, laid the foundation for the development of this important new type of titrimetry. Professor Irving is well k n o w for his extensive fundamental work on the structures and stabilities of chelate complexes, especially those involved in precipitation and extraction of metals with organic reagents. An outsthnding feature of this book is the logical and systematic treatment of the equilibria involved in visual titrations, using ethylenediaminetetraacetic acid (EDTA) and to a minor extent nitrilotriacetic acid (NTA) as reagents. The equilibria include (a) formation of the complex between metal ion and reagent, ( 6 ) effect of pH on the reagent, ( c ) the formation of complexes with secondary complexing agents, such as z m o n i a , (d) the formation of complexes between the metal ion and indicator ion, and (e) the effectof pH on the indicator. The effects of pH are Logically considered in terms of competition between hydrogen ions and metal ions for the reagent or indicator anion. Thus the reciprocals of the usual stepwise ionization constants of an acid are recarded as the formation oonstants of the is considered in terms of competition between reagent anion, the indicator, and secondary complexing agents for the metal ion. I t might appear that such an array of equilibria would be most cumbersome to handle. However, with the unifying treatment and the simplifying assumptions VOLUME 35, NO. 5, MAY, 1958

made possible by the fact that the metal ion concentration is generally very low (typically of the order of 10-SM), the titration curve calculations become quite straightforward. This volume cannot be regarded as a. textbook or as a comprehensive book of procedures. Yet it can be highly recommended both for the advanced student and the practicing analyst as a valuable guide to the principles. I t is ehssacteristic of thia rapidly pragressing field that e book must be out of date in certain respects immediately upon publication. Thus, the work of Reilley on the use of the mercury-EDTA complex rts a. source for the coulometric generation of EDTA is mentioned only in the translator's preface, and his use of the mercuryEDTA potentiometric indicator electrode is not mentioned a t all. Likewise, the recent literature contains numerous references to new metal ion indicators. Very few typographical errors were noted, but the quality of the paper is poor. H. A. LAITINEN U N ~ V E ~ ~OPLITL Y LINOI~ Une*w*. I ~ ~ r l r o m

PHYSIC0 CHEMICAL EXPERIMENTS Robert Livingston, Professor of Physical Chemistry, University of Minnesota. Third edition. The Macmillan Co., New 273 ppp. 69 figs. York, 1957. xiv 11 tables. 1 4 X 21 cm. $4.50

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THIS is the third edition of a very useful laboratory manual in physical chemistry. I t was first published in 1939 and revised in 1948. To undertake a critical reevaluation every nine years indicates dertness in a field that is constantly in a state of flux ss regards its emphases. The manual is very well adapted to the first year course in liberal arts colleges where no graduate department of chemistry is a t hand. So often equipment is limited in these institutions. Elaborate experiments require such extensive revision that an instructor is encouraged to write his own procedures. This manual has much to commend i t in that enough variety of experiments is st hand to accommodate any respectable laboratory. Two new experiments have been added, one on the determination of dipole moment and another on the determination of transference numbers by the moving boundary method. The omission of the classic Victor Meyer determination of molecular weight will cause some dismay, but the author makes a good case for its dismissal, even though he retains the equally classic but more simple Dumas determination. There are several eommendsble features.

The first 51 page8 deal in excellent detail an Measurements, Errors, and Computations. A section on Dimensions and Approximate Computations is north noting. Too often these matters are overlooked in a com'sc m physical chemistry. The sections on Theory of Errors and A p plieation of Error Theory deserve high prai~ise,both for their presentation and for the simple fact that they were included. The section on Evaluation of the Constants of Empirical Equations is, to this reviewer, worthy of special mention. All of this introductory part of the book substantiates the conviction that students should know how to handle data, how to evaluate, and how to determine its degree of rerpectability. Another fine feature of this manual is the inclusion in a separate section, but along with the experiment, an explanation and details of operation of some of the standard pieces of equipment found in a physical chemistry laboratory. Some of these are the Westphal balance, polarimeter, Beckm m n differential thermometer, student's potentiometer, colorimeter, spectrophotometer, even a Sprengel pycnometer. Another helpful feature is that the author is not hesitant in making references to more elaborate sources suih as Weissberger, Kolthoff & Sandell, McDougall, Moore, and Guggenheim & Prue. Many original sources are mentioned in the literature as well as other monographs. This is an excellent laboratory manual. It includes s. fine range of 42 experiments covering all fields of elementary physical chemistry. These are all well set up with a concise theoretical introduction, an itemieed list of apparatus and materials, and successive sections on procedure and computations. 6. J. VELLENGA

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MISES AU POINT DE CHIMIE ANALYTIQUE PURE ET A P P L I Q U ~ET D'ANALYSE BROMATOLOGIQUE. VOLUME IV Edited by J. A. Goutier, Professor of the Faculty of Pharmacy of Paris. Masson et Cie, Paris, 1956. 212 pp. 21 figs. 16.5 X 2 5 a n . Paper bound, 2400 fr.

TEEfourth volume of these progress reports deals mostly with methods af interest to the biochemists and the food chemists. I t should be interesting to Americans for the reason that one may expect reasonably complete coverage of the French literature and possibly of the liter ature from Latin countries.