ultrasonic study of molecular interactions in liquid mixtures

Abstract

Ultrasonic techniques have been an important tool and means in understanding the molecular interactions in liquids and liquid mixtures. Molecular interactions provide an understanding the fundamental problems concerned with the mechanism of biochemical and chemical catalysis. The study of molecular interactions is of so much significance in physics, chemistry, dentistry, polymers, engineering and biology. Ultrasonic techniques are comparable to other probing techniques like Infrared (IR), Nuclear Magnetic Resonance (NMR) and dielectric relaxation etc. newlineThe knowledge of excess thermodynamic parameters is highly essential in indicating the nature of interaction between the like and unlike molecules, endothermic or exothermic reactions etc. Variation of excess parameters with temperature yields the information about the type of interactions when a solute is added to the solvent (Polar, Non polar, weekly polar etc.). newlineIntermolecular interactions classified into two types. They are 1.Short range forces and 2.Long range forces. Short range interactions are due to charge transfer complex formation and hydrogen bond interaction. A vast amount of experimental data exists and many theoretical approaches have been developed in attempting to explain these interactions. The long-range forces are electrostatic, induction and dispersive forces. Long range forces arises when intermolecular separation between the interacting molecules is close enough without overlap of electron clouds, and hence mainly depend on intermolecular separation. Long range interaction forces leads to the existence of Vander Waal forces between dipole dipole and dipole- induce dipole molecules. newlineThe study of partial molar volumes not only explains the molecular interactions but also supports the results observed from the excess parameters.A good survey of the viscosity data, its critical evaluation and correlation would help design engineers, scientists and technologists in their areas of interest.