Isentropic Compressibility Studies of Some Salts in Acetonitrile + N,N-dimethylacetamide Mixtures at 298 K

Abstract

Abstract Ultrasonic velocities and densities of some copper(I) and silver(I) salts have been measured in the concentration range 0.002–0.28 mol kg−1 in binary mixtures of acetonitrile (AN) + N,N-dimethylacetamide (DMA) containing 100, 80, 60, 40, 20 and 0 mol % AN at 298 K. The isentropic compressibility (K s) and apparent molal isentropic compressibility in various solvent systems have been calculated by using ultrasonic velocity (u) and partial molal volume (V φ ) respectively. Limiting apparent molal isentropic compressibilities (K s,φ 0) for various salts have been evaluated from vs. m 1/2 plots and split into the contributions of individual ions (K s,φ 0)±. The (K s,φ 0)± values for copper(I) and silver(I) ions are found to be negative over the entire composition range which indicate strong solvation of these complex ions. The (K s,φ 0)± values for these ions increase with increase in DMA composition shows that the extent of solvation increases with increase in DMA composition.