Electrolytes in mixed solvents: indium trichloride in water–dimethylsulfoxide mixtures

Abstract

This paper is concerned with the investigation of the conductances (some 160 determinations) of potassium chloride and of indium trichloride in water-dimethylsulfoxide mixtures. The behaviour of potassium chloride in these mixtures is practically identical with its behaviour in water, up to 50 wt% DMSO. Thus Walden's rule is followed very closely, implying that the only effect on the speeds of the ions is that of viscosity. The behaviour of indium trichloride is very different. The conductance increases rapidly with dilution, in the dilute region, and it is time dependent. It is practically certain that the ionization of indium trichloride takes place in steps and that, in dilute solution, progressive hydrolysis occurs. By extrapolating the measurements as a straight line, below concentrations of 0.01 N, an approximation to the limiting value of Λ is obtained.