Viscosity, apparent molar volume and thermodynamic parameters of lanthanum chloride in absolute and aqueous ethanol mixtures

Viscosities and apparent molar volumes of different concentrations of lanthanum chloride from 1x10-2 to 9x10-2 mol dm-3 have been studied in absolute and aqueous ethanol mixtures at temperatures ranging from 303 to 323 K. viscosity and density data were analyzed by using two different relations for the prediction of nature of lanthanum chloride in absolute and aqueous ethanol systems. A and B-coefficients of Jones-Dole equation show ion-ion and ion-solvent interactions respectively. The density data was analyzed in terms of limiting apparent molar volume (vo) and experimental slopes (Sv) obtained from Masson equation has been used to interpret the ion-solvent interaction and ion-ion interaction respectively. On the basis of results evaluated by using the different parameters it was concluded that lanthanum chloride behaves as a structure maker in absolute ethanol and 90 % (v/v) aqueous ethanol, while as the aqueous quantity increases such as 80 to 70 % (v/v) it behaves as structure breaker. Thermodynamic parameters such as energy of activation (E ), free energy change of activation (ΔG*) and entropy change of activation (ΔS*) for viscous flow have been evaluated as a function of concentration, solvent and temperature.