Probing Aqueous Electrolytes with Fourier Spectrum Pulse-Echo Technique

Abstract

The nature of variations of ultrasonic wave velocity(v) and attenuation constant({\alpha}) with the concentration(c) in aqueous solutions of NaCl, KCl and CsCl are investigated at room temperature(250C) at 1MHz and 2 MHz wave frequency. Fourier Spectrum Pulse-Echo (FSPE) technique is used to achieve better accuracy in measurement, particularly for {\alpha} measurement. In NaCl and KCl abrupt changes in the values of v and {\alpha} are noticed at particular solution concentrations whereas, for CsCl almost smooth variation in v is observed over the whole concentration range for both of the frequencies 1 and 2 MHz . The nature of variation in v and {\alpha} in these solutions are analyzed in view of other spectroscopic studies. The well-known Jones-Dole equation that explains the viscosity({\eta}) variation in many electrolyte solutions, offers satisfactory fits to the experimental velocity variation with parameter values characteristics of the sample.