Isentropic compressibility and viscosity of aqueous and methanolic lithium chloride solutions

Abstract

Densities, speeds of sound, and viscosities of aqueous and methanolic lithium chloride solutions were measured as functions of concentration, m (mol kg–1) (0.3911 [Formula: see text] m [Formula: see text] 19.47) and temperature (273.15 [Formula: see text] T [Formula: see text] 323.15 K). Measured values of the density, speeds of sound, and viscosity agree well with previously reported data. The isentropic compressibility isotherms for the aqueous solutions converge at a particular concentration, in the temperature range of the study, providing crucial information regarding the solvation behaviour of the ions. However, for the methanol solutions, the isentropic compressibility isotherms decrease smoothly with concentration and converge on extrapolation. Anion solvation controls the viscosity processes at low temperatures whereas cation solvation controls the same at high temperatures. Total primary solvation numbers of lithium chloride in water and methanol were estimated to be 6.0 and 1.9, respectively.Key words: lithium chloride, speeds of sound, viscosity, isentropic compressibility, solvation number.