Study of Water and Water–Ethanol Solutions of Potassium Salts Through Ultrasonic and Spectroscopic Approach

A simpler but accurate method of analyzing the interactions between the molecules of liquids and solutions is through Ultrasonic study. This paper focuses the study of acoustic and thermodynamic behaviour of water and the mixture of water and 20% ethanol solutions of Potassium Acetate and Potassium Metabisulphite (Preservatives) and also explains the nature of interactions between the molecules in liquids and solutions. The ultrasonic velocity, viscosity and density are measured for the prepared solutions various concentrations at different temperatures ranging from 35ºC to 55ºC at the interval of 5ºC. Using the above data, acoustic and thermodynamic parameters such as adiabatic compressibility, intermolecular free length, specific acoustic impedance, Rao’s constant, Wada’s constant, internal pressure and free volume are evaluated and their variations with respect to concentration and temperature are studied. The change in acoustical and thermodynamical parameters with respect to concentration and temperature has been used to interpret various molecular interactions in water and water–ethanol solution of Potassium salts. Solute–solvent interaction seems to be significant in the chosen solutions. A quantitative study shows that at a given concentration, the variation of πi with Vf due to a change in temperature and the variation of internal pressure structure breaking or structure making nature of the solution is analyzed. FTIR analysis is used as a supportive study for understanding the behaviour of the water and water–ethanol solutions, particularly for understanding the hydrogen bonding interactions. The frequency shift towards the higher wave number side for the solution and the obtained results are interpreted and discussed.