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Dielectric constants, densities, and viscosities of N‐methylacetamide, dimethylformamide, and of mixtures of these liquids have been determined at five temperatures. Conductances, densities, and viscosities of solutions of sodium and potassium bromides and potassium iodide in various mixtures of these solvents have been measured at ten‐degree intervals from 20° to 50°C. Variations in the dielectric constant of the solvent over the range 35–165 showed no influence on the degree of dissociation of these salts; they are essentially completely dissociated in all of the solvent mixtures studied. Differences in mobilities of the ions are explained in terms of various specific types of solute‐solvent interactions.

RECEIVED AUGCST 30, 1934 Conductances, densities and viscosities of solutions of lithium chloride and of potassium and sodium chlorides, bromides and iodides in N-methylacetamide have been measured within the temperature range from 30 to 60" for concentrations which ranged from 5 X 10-4 to 1.0 or 2.0 molar. Kohlrausch plots for all of the systems exhibit relatively good agreement with the Onsager limiting equation to concentrations of 0.01 molar or more. Plots of the product of the equivalent conductance and the square root of the relative viscosity of the solution versus the square root of the concentration yield straight lines to 0.3 molar or above. The Kohlrausch law of independent ion mobilities is shown to be valid in these solutions.

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The conductances of several quaternary ammonium bromides and iodides in dimethylformamide have been measured at 25°. In each case, the observed slope of the plot of the equivalent conductance versus the square root of the concentration was more negative than that predicted by the Onsager equation. Limiting equivalent conductances and dissociation constants have been determined by the Shedlovsky extrapolation method. The quaternary ammonium halides being dissociated to a lesser extent than some potassium and sodium halides is strong evidence that the latter cations are rather highly solvated in dimethylformamide. Bromides were found to be 1.6 ± 0.1 ohm-1 cm.2 more conducting than the corresponding iodides. Data are presented showing that the ratio of the conductance in acetone to that in dimethylformamide is 2.32 ± 0.09 for each of seventeen salts.