Considerable work has been done in this laboratory, especially during the past five years, on the conductivity and dissociation of organic acids in water as a solvent, over a fairly wide range of temperature and dilution. This investigation is a continuation of those in non-aqueous and mixed solvents, which have been in progress in this laboratory during the past dozen years2 Since, up to the present but very little has been done here with solutions of the organic acids in absolute ethyl alcohol, it was decided to extend our investigations into this field.3 A few rather crude measurements of the conductivity of organic acids were made comparatively early in the history of the conductivity method. W a k e~n a n ,~ in 1893, measured the conductivities of certain organic acids in mixtures of alcohol and water, ranging from pure water to 5 0 7~ alcohol. He calculated the dissociations of these acids and their dissocia-This investigation was carried out with the aid of a grant t o H. C. Jones from the Carnegie Institution of Washington.
The hydrolysis of the chlorides and nitrates, etc., of calcium, magnesium, strontium and barium employed in the study of this problem, is so small that it alone cannot account for the results obtained. (3) Salts with water of crystallization increase the velocity of the saponification of an ester to a greater extent than salts with no water of crystallization. (4) On dilution, the effect with salts having water of crystallization decreases more rapidly than with salts without crystal water, which shows that the result cannot be due to hydrolysis alone. (5) The curves for the saponification of methyl formate are very similar to those for methyl acetate. (6) The large effect of salts with water of crystallization is probably due, in part, to their being hydrated, combined water being more highly ionized than free water. (7) The amount of the saponification, and, therefore, the position of the curve seems to be due to the combined effect of both cation and anion. (8) It is probable that anions as well as cations are somewhat hydrated. (9) The hydration of cations is inversely proportional to their atomic volumes. (IO) There seems to be a dilution of maximum saponification for each salt, (11) Hydrated salts show a large temperature coefficient, notwithstanding the decomposition of hydrates with rise in temperature, probably due in part to hydrolysis. (12) Decomposition of hydrates may play an important role in the increased velocity of chemical reactions with rise in temperature. (13) The chemical differences between free and combined water are analogous to the physical differences. Further work is riow in progress in this laboratory on this problem. Certain apparent discrepancies in this preliminary communication are being further investigated, and other lines of attack opened up. BALTIMORE. MD. [CONTRIBUTION FROM THE DEPARTMENT OF CHEMISTRY OF THE JOHNS HOPKINS UNIVERSITY.
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