Ultrasonic Studies of Molecular Interactions in Ternary Liquid Mixtures at Different Temperatures

The behavior of mixture of pyridine, N- N dimethylformamide and cyclohexane as a function of
temperature and composition has been investigated by measuring ultrasonic velocity in conjunction with
density and viscosity at 288, 298, 308 and 318 K for frequency 2 MHz. From the velocity, density and
viscosity data values, various acoustical and thermodynamics parameters namely, adiabatic
compressibility (β), intermolecular free length (Lf), viscous relaxation time (τ), Gibbs’ free energy (ΔG),
internal pressure (Пi) free volume (Vf) and specific acoustic impedance (Z) have been calculated. Also
their excess values are calculated. All these parameters and their excess values have been discussed to
throw light on intermolecular interactions between the components of ternary mixture.