Study of variation of optical and physical properties of saline water solutions with temperature

Abstract

Measurements of refractive index, ultrasonic velocity, density and viscosity of pure water, aqueous NaCl solutions of various concentrations, and sea water collected from Diu sea shore (Gujarat, India), were carried out at temperatures of 20°, 30° and 40 °C. To determine the ultrasonic velocity, density and viscosity; the ultrasonic interferometer, pycnometer and Oswald’s viscometer were used, respectively. For the measurement of refractive index of these solutions at various wavelengths, the LEDs (Light Emitting Diodes) emitting radiations of different wavelength were used along with the Abbes refractometer. Experimental values of refractive indices have been compared with the values calculated using an empirical equation given by McNeil (1977) and Matthus (1974) and are in good agreement with the literature values. Experimental values of ultrasonic velocity of different solutions agree very well with the values calculated using the empirical equation given by Medwin (1975). Acoustical parameters like acoustic impedance (Z), adiabatic compressibility (βa) and intermolecular free length (Lf), were obtained by using values of ultrasonic velocity and density.