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

摘要

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-dimefhylacetarnide (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)0~0) 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.