ION-SOLVENT INTERACTION OF SODIUM IODIDE AND LITHIUM NITRATE IN N, N-DIMETHYLFORMAMIDE + ETHANOL MIXTURES AT VARIOUS TEMPERATURES

The densities, viscosities and ultrasonic velocities of sodium iodide and lithium nitrate in dimcthylformamide + ethanol mixtures have been measured as a function of amide concentration and temperature. Viscosity and ultrasonic velocity are fitted by empirical equations stating their dependence on composition of the mixtures. The adiabatic compressibility, intermolecular free length, relative association, acoustic impedance, molar sound velocity, enthalpy and entropy of activation of viscous flow have been calculated. The variations of these properties with amide concentration in the mixtures indicate strong ion-solvent interaction. Preferential solvation of the ions is also discussed.