Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

The electrical conductances of the solutions of tetrabutylammonium bromide (Bu4NBr), sodium tetraphenylborate (NaBPh4), and sodium bromide (NaBr) in methanol (1) + water (2) mixed solvent media containing 0.10, 0.20, and 0.30 volume fractions of methanol have been reported at (298.15, 308.15, and 318.15) K. The conductance data have been analyzed by the 1978 Fuoss conductance-concentration equation in terms of the limiting molar conductance ($0), 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". All of these three electrolytes are found to exist as free ions in the present solvent mixtures within the temperature range (298.15 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 play a profound influence on their mobilities. Although the association constants of the electrolytes do not vary significantly as a function of temperature, the limiting molar conductances of the electrolytes as well as the single-ion conductivity values increase appreciably with temperature.