EFFECT OF FREE-VOLUME AND INTERNAL-PRESSURE ON ION-SOLVENT INTERACTION OF SOME AQUEOUS ELECTROLYTIC SOLUTIONS

Ultrasonic velocity of magnesium, calcium and barium chlorides in 10, 20 and 30% dioxane-water mixtures have been measured at different conc entrations of the salts and different temperatures. The free volume an d internal pressure of the aqueous solutions were calculated from the measured sound velocity, density and viscosity. The results were discu ssed in terms of the structural changes around the ion and the effect of the solvent. At a fixed dioxane content and at a particular concent ration of the electrolyte, the free volume is found to increase (decre ase in internal pressure) with the decreasing charge density of the ca tions. For any given concentration, the variation of internal pressure and free volume obeys the relationship pi(i) V(f)X = K in accordance with the previous results.