Direct measurement of acoustic impedance in liquids by a new pulse echo technique

For the first time a novel experimental technique has been used for direct evaluation of acoustic impedance of liquids. Till date researchers have been using ultrasonic velocity and density measurements to compute acoustic impedance and thermodynamic parameters, which are then used to investigate the nature of molecular interactions of solvent molecules in binary, ternary and quaternary liquid mixtures. Evaluation of acoustic impedance directly is a step in minimizing the cumbersome process of measuring velocities and densities separately of solutions having different mole fraction concentration. Acoustic impedances of ten pure polar and non polar solvents have been determined at different temperatures of 298K, 303K and 308K. This is further coupled with inline simultaneous determination of ultrasonic velocities of the solvents. In order to establish the new method, results have been discussed by comparing the calculated ultrasonic velocity from the experimental acoustic impedance, ultrasonic velocity determination by delay time of flight and the literature values of ultrasonic velocity of the pure solvents.