Ultrasonic Investigation of Hydrogen Bonded Complexes of Aniline with CHCl3 and CH2Cl2

Molecular association study of aniline - chloroform and aniline – methylene dichloride systems in n-hexane was carried out at 293, 298, 303 and 308 K from the measurement of ultrasonic velocity, density and viscosity. The formation of thermodynamically stable hydrogen bonded complex between aniline and CH2Cl2 as well as CHCl3 is established from the trend in acoustical properties and from the variation in the excess parameters with concentration. Formation constants of these complexes are calculated at four different temperatures by ultrasonic method and from the K values at four different temperatures. Thermodynamic parameters such as free energy change (∆G), enthalpy change (∆H) and entropy change (∆S) for the formation of these complexes are evaluated.