Thermodynamics of mixed electrolyte solutions. V. An isopiestic study of the aqueous systems tetra-n-propylammonium bromide-sodium bromide and tetramethylammonium bromide-sodium bromide at 25°C

Osmotic and activity coefficients were measured by the gravimetric isopiestic vapor pressure technique in the aqueous systems tetramethylammonium bromide-sodium bromide and tetra-n-propylammonium bromide-sodium bromide. The excess Gibbs free energy of mixing and Friedman's interaction coefficients were obtained and interpreted in terms of ion-ion interactions leading to self-salting-in in the case of the Pr₄NBr-NaBr-H₂O system and to salting-out in the case of the Me₄NBr-NaBr-H₂O system.