Electrical Conductances of Tetrabutylammonium Bromide, Sodium Tetraphenylborate, and Sodium Bromide in Acetonitrile (1) + Water (2) Mixtures at (308.15, 313.15, and 318.15)K

Abstract

The electrical conductances of solutions of tetrabutylammonium bromide (Bu4NBr), sodium tetraphenylborate (NaBPh4), and sodium bromide (NaBr) in acetonitrile (1) + water (2) mixed-solvent media containing 0.20 and 0.40 volume fractions of acetonitrile have been reported at (308.15, 313.15, and 318.15) K. The conductance data have been analyzed by the 1978 Fuoss conductance−concentration equation in terms of the limiting molar conductance (Λ0), the association constant (KA), and the association diameter (R). The ionic contributions to the limiting molar conductance have been estimated using tetrabutylammonium tetraphenylborate (Bu4NBPh4) as the “reference electrolyte”. These three electrolytes are found to exist as free ions in both solvent mixtures in the temperature range of (308.15 to 318.15) K. Besides the relative permittivity and the viscosity of the media, specific interactions of the ions with the solvent media have been found to exhibit a profound influence on their mobilities. Although the association constants of the electrolytes do not vary significantly as a function of temperature, the limiting equivalent conductances of the electrolytes as well as the single-ion conductivity values increase appreciably with temperature.