Limiting partial molar volumes of Potassium aluminium sulphate in dimethyl sulphoxide + water at different temperatures

Abstract

Densities of potassium aluminium sulphate have been measured in dimethyl sulphoxide (DMSO) + water, containing 0, 5, 10, 15, and 20 mass percent of DMSO, at different concentration and at 298.15, 303.15, 308.15 and 313.15 K. From the densities, apparent molar volumes have been derived. The apparent molar volume data have been analyzed using Masson equation. The limiting molar volumes, vф 0 , and Sv * slop are interpreted in terms of solute-solvent and solute-solute interactions respectively. The vф 0 values vary with temperature as power series of temperature. Finally, the structure making/ breaking capacities of salts have been inferred from the Hepler's criterion. I. Introduction Thermodynamic investigation play important role in understanding type and extend of the pattern of molecular associations that exist in liquid mixtures and their sensitivities to variation in composition, temperature, pressure and chemical nature(1). The partial molar of salt is an important thermodynamic property. Ion-solvation (2-4) and electrochemical studies (5-6) in aqueous-DMSO are popular. So the thermodynamics of ion-solvent interaction in this system is of considerable importance. As partial molar volumes of a solute reflects the cumulative effects of ion-ion and ion-solvent interactions (7-8), it would be of interest to study partial molar volumes of potassium aluminium sulphate a in dimethyl sulphoxide(DMSO) + water system.