Partial molar and ultrasonic properties of benzoic and phenyl acetic acids in water and water plus alcohol mixtures

Partial molar volumes of Benzoic and Phenylacetic acids have been determined in water and water + alcohol (5 wt% each of methanol, ethanol and propanol) mixtures from density measurements in varying ranges of concentration at four different temperatures in the interval of 10 degrees from 288.15 to 318.15 K. The density data have been used to obtain partial molar volumes, co-efficients of thermal expansion and partial molar expansibilities of the acids in these solvents. Studies on sound velocity have been made in aqueous and aqueous alchohol solutions of these two acids to evaluate various acoustic parameters at 303.15 K. The solvation numbers of these acids have been determined in these solvents. The results are discussed in terms of ion-ion and ion-solvent interactions and of structural effects on the solvent in solution.