Ultrasonic velocity, viscosity, density and excess properties of binary mixture of dimethyl sulphoxide with propanoic acid and n-butyric acid

Ultrasonic velocity (u), viscosity (η) and density (ρ) have been measured for binary mixtures of dimethyl sulphoxide (DMSO) with propanoic acid (PA) and n-butyric acid (BA) at three temperature 293 K, 303 K and 313 K, over the entire range of composition. Deviation in isentropic compressibility ΔβS, deviation in viscosity Δη and excess free energy of activation for viscous flow ΔG⁎E have been calculated using experimental values of ultrasonic velocity (u), density (ρ) and viscosity (η). Deviation in isentropic compressibility (ΔβS) and viscosity (Δη) as well as excess free energy of activation for viscous flow (ΔG⁎E) were plotted against the mole fraction of DMSO over the entire composition range. The values of ΔβS have been found to be negative whereas the values of ΔG⁎E and Δη were positive for both the mixtures over the entire composition range. The strength and the nature of interaction between the molecules of DMSO with propanoic acid and n-butyric acid have been discussed.