Thermal Expansivity and Isothermal Compressibility of Binary Liquid Mixtures from Ultrasonic Velocity:A Comparison to Flory's Theory and Hard Sphere Models

Thermal expansion coefficient and isothermal compressibility of binary liquid mixtures of varying nature have been calculated using density and ultrasonic speed data. Excess thermal expansivity, and isothermal compressibility of binary liquid mixtures have also been calculated and the results are interpreted in terms of strength of molecular interactions between the component molecules of the liquid mixtures. Moreover, thermal expansion coefficient and isothermal compressibility of pure liquids and liquid mixtures has been calculated using Flory's theory and various hard sphere models. The results are useful in predicting the superiority of Flory's theory over the hard sphere models in predicting the above properties.