Studies in Ion Solvation in Non-aqueous Solvents and Their Aqueous Mixtures: Part 15.1—Free Energies of Transfer of Cadmium Chloride from Water to 10-40 % (w/w) Methanol-Water Mixtures at 25°C; Dissociation of CdCD; Use of Dilute Cadmium Amalgam Electrodes. The Group II Cations

Abstract

The cell Cd(Hg) | CdCl2 | AgCl—Ag has been used to obtain the standard molar free energies of transfer, AGt, of cadmium chloride from water to 10 %, 20 % and 40 % (w/w) mcthanol-water mixtures. Cadmium chloride is a weak electrolyte. This was allowed for in computing the standard e.m.f. values of the cell; dissociation constants of CdCl F were also determined. The behaviour of the Group II cations, Cd2+, Zn2+, Sr2+ and Ba2+, in the methanol-water system is discussed in terms of the “ acid-base ” theory and their “ hardness ” or “ softness ” as Lewis acids, and they are briefly compared with the univalent cations of Group I.