Treadwell F.P. Analytical Chemistry. Volume 2. Quantitative Analysis

Translated from the German and revised by William T. Hall. — New York: John Wiley & Sons; London: Chapman & Hall, 1915. — 956 p.This translation has been made from the second German edition, but Professor Treadwell has kindly indicated quite a number of changes which he intends to make in the third edition.In preparing the second edition, the text has been compared with the fourth German edition, and certain additions have been made which are not found in the German text. W. T. H. - March, 1910.
The third edition has been compared with the fifth German edition. In the preparation of dilute acids the volume of concentrated acid is always referred to the volume of water added.
Thus sulphuric acid (1:4) signifies one volume of concentrated - acid diluted with four volumes of water. With solutions of solids, the first number signifies the weight in grams of the solid and the second the volume of the solvent in cubic centimeters.Having been repeatedly requested by former pupils to publish the lectures on Analytical Chemistry given by me at this Institute since 1882, and not having time then to do it myself, I permitted the ‘“‘ Verein der Polytechniker ” in 1885 to print in manuscript form the notes of one of my students.
This output met with such a friendly reception that in 1888 a second edition became necessary. Subsequently I decided to revise the material thoroughly and publish it in book form; this text-book of Analytical Chemistry represents, therefore, a somewhat amplified repetition of my lectures.
The book is intended not only for laboratory use, but also for self-study. With each element the mineralogical occurrence, crystalline form, and isomorphous relations are briefly mentioned. Then, after explaining the reactions, the methods of separation are given in the form of tables; because, contrary to the views of many, I have
in this way obtained the best results in teaching. These tables are summarized charts by which the student can quickly find his bearings.
Much weight is placed upon the determination of the sensitiveness of the single reactions, as explained on page 75, because the beginner becomes in this way at once familiar with the solubility of the most important salts, and also with simple stoichiometrical calculations. The approximate solubility of potassium chloroplatinate, for example, is found from the following determination of the sensitiveness of the reaction by which it is formed:
If 100 cc. of the solution contain 0.156 gm. potassium, one finds that the formation of the chloroplatinate, at ordinary temperatures, only takes place on addition of a little alcohol; but on increasing slightly the amount of potassium in the solution, it takes place immediately. We can, therefore, assume that the solution, which con-tains 0.156 em. of potassium per 100 cc. water, is saturated with chloroplatinate; hence the amount of the latter may be calculated:
Ke : KePtCle =0.156 : x;
78.3 : 485.8 =0.156 : a;
z=0.97.
The result shows that 100 cc. of water, at ordinary temperatures, dissolve 0.97 gm. of K2PtCle, while accurate determinations at 20° C have given the value 1.12. The difference, about 12 per cent, isexplained by the facts that we did not work at exactly 20° C., nor with absolutely pure water; the solution also contains an excess of
chloroplatinic acid, whereby the solubility of the potassium chloroplatinate is diminished; evidently the values obtained in this way permit a very good comparison of the solubilities of the different salts. From the sensitiveness of the reaction between a potassium salt and tartaric acid, the solubility of the potassium acid tartrate may be found to be 0.38; so that the solubility of the potassium chloroplatinate is to that of the potassium acid tartrate as 0.97 : 0.38; the potassium tartrate is about three times as insoluble as the chloroplatinate, etc.
The size of the book does not permit going into the microchemical detection of the different elements. We have, however, in the
excellent work of H. Behrens, ‘ Anleitung zur mikrochemischen Analyse,’’ a reference book of the highest rank.