Anomalous Ultrasonic Attenuation in Aqueous NaCl Solutions

The velocity (v) and attenuation constant (a) for ultrasonic waves of frequencies 1MHz and 2MHz propagating through aqueous sodium chloride solution have been measured over the concentration (c) region 0-5.3 mol.L-1 at room temperature (250 C). The velocity (v) shows an overall increase with the increase of c indicating comparatively stronger bonding among the ions and water molecules prevailing in the solution. The attenuation constant, besides showing an overall increase with c, shows significantly high values at some concentrations. Attempt has been made to understand the behaviour from existing theoretical background.