Anomalous Ultrasonic Attenuation in Aqueous NaCl Solutions

TL;DR

This study measures ultrasonic wave velocity and attenuation in aqueous NaCl solutions across various concentrations, revealing increased attenuation at certain points and suggesting stronger ion-water bonding with higher salt content.

Contribution

It provides new experimental data on ultrasonic attenuation and velocity in NaCl solutions, and analyzes their behavior in relation to ion-water interactions.

Findings

Velocity increases with salt concentration.

Attenuation shows peaks at specific concentrations.

Stronger ion-water bonding inferred from velocity data.

Abstract

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.