[CONTRIBUTION FROM THE
MASSACHUSETTS INSTITUTE O F TECHNOLOGY.]
REVIEW OF AMERICAN CHEMICAL RESEARCH. VOL. V. No. IO. ARTHURA. NOYES,Editor. REVIEWERS:Analytical Chemistry, H. P. Talbot and W. H. Walker; Biological Chemistry, A . G. Woodman ; Carbohydrates, G. W. Rolfe ; General Chemistry, A. A. Noyes ; Geological and Mineralogical Chernistry, W. 0. Crosby and M. L. Puller ; Inorganic Chemistry, Henry Fay ; Metallurgical Chemistry and Assaying, H. 0. Hofman ; Organic Chemistry, J. F. Norris ; Physical Chemistry, H. M. Goodwin ; Sanitary Chemistry, E. H. Richards; Technical Chemistry, A. H. Gill and F. H. Thorp.
GENERAL AND PHYSICAL CHEMISTRY. A. A.
NOYES, REVIEWER.
The Theoryof the Formation of Nickel Sulphide.
BY J.
LIVINGSTON R. MORGAN, A N D A. H. GOTTHELF.J . Am. Chem.SOC., 21, 494-502.-The authors attempt to show that the well-known fact that nickel and cobalt sulphides when once formed are not dissolved by acids of a concentration much greater than is required for preventing entirely their precipitation by hydrogen sulphide, can be explained simply by an application of the principles of mass-action and of electrolytic dissociation, assuming an appropriate value for the solubility of the sulphides. T h e considerations of the authors are, in the reviewer’s opinion, erroneous in some essential points ( t h u s this is true of the statements that no undissociated nickel sulphide or hydrogen sulphide will be formed till the product of the concentrations of their respective ions reaches the value of the ‘‘ solubility-product”), but it is unnecessary to discuss these in detail, since it is a priori evident that the principles of equilibrium a s ordinarily applied cannot possibly explain the phenomenon in question ; for, if equilibrium exist between the four substances, NiCl,, H,S, HCl, and NiS (solid), when the first two are present in large amount and the last two in very small amount, it is clear that the conditions must be farremoved from those of equilibrium when the last two compounds are alone brought together, and conversely. T h e probable explanation, Foundations of Anapreviously suggested by Ostwald (Scientific @tical Chemistry,p. 14g), of this apparent anomaly, is that after precipitation the nickel sulphide rapidly undergoes a change in its chemical nature (perhaps a dehydration), the new form being
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much less soluble in water and therefore in acids than the original one. By quantitative experiments Ostmald has proved that this is the case with zinc sulphide, and the same property, in D much more pronounced degree, seems to be possessed by nickel and cobalt sulphides.
The Effect of Diionic Electrolytes on the Solubility of Triionic Electrokytes with Different Ions. BY - ~ R T H U R A. NOYES A N D EDWARD S. CHAPIN. J . A m . Chem. SOC., 21, 511-516.T h e authors derive the theory of the phenomenon mentioned in t h e title and communicate experiments confirming it on the solubility of calcium hydroxide in water and ammonium chloride solutions. The Theory of the Separation of Barium, Strontium, and Calcium from the Mixed Sulphates. BY J . LIVINGSTON R. MORGAN. J . Am. Chem. SOL.,21, 522-526.--It is shown that the separation of t h e sulpliates named, by ammonium carbonate or a mixture of potassium sulphate and carbonate, is readily explained by the dissociation theory and the laws of solubility-effect. The Atomic Ilass of Tungsten and the Preparation of Sodium Pertungstate by Means of the Electric Current. BY GEORGEEDWARD THOMAS. J . Am. Chem. Sac., 21, 373-381.I n the first part of the article it is shown that two samples of tungsten trioxide, prepared from distinct minerals, scheelite and wolframite, are apparently identical, but that both of them fail to give concordant values of the atomic weight when reduced to t h e metal or when t h e latter is reoxidized ; also that the method of determining the atomic weight from the loss of weight occurring when crystallized sodium tungstate is heated sufficiently to expel the water is an unsuitable one. I n the second part the author describes the results of electrolyzing sodium tungstate, considering that a pertungstate is formed thereby, since a substance liberating chlorine, iodine, and ozone was obtained, though not in a state of even approximate purity. The Surface-Tensions of Aqueous Solutions of Alkaline Chlorides. BY C. E . LINEBARGER. J . A m . Ckem. SOL.,21, 41 1-415.-Equimolecular solutions of potassium, sodium, and lithium chlorides are found to have t h e same surface-tension ; and their surface-tension is found to be only approximately a linear function of the concentration.
