Abstract: The thermodynamic and acoustical study elucidates the nature of interactions between molecules in liquids and solutions. Also ultrasonic parameters are directly related to a number of thermodynamic parameters. As the different liquid state theories are based on thermodynamic considerations, the study of propagation of ultrasonic waves in liquid systems is established as a simple and effective tool in determining the nature of interactions between molecules in liquids and solutions. Using ultrasonic velocity measurements, Adiabatic Compressibility, Rao’s Constant, Wada’s Constant, Specific Acoustic Impedance and Intermolecular Free Length are evaluated and the variations are analyzed. Structure making and Structure breaking nature of solution is studied using Internal Pressure variations.