Abstract
In non-aqueous polarography, the standardization of electrode potential involves some difficulties such as preparation of the reference electrode with non-aqueous solvent or evaluation of the junction potential between aqueous and non-aqueous solutions'. One of the methods is to compare the half wave potential with that of the reference substance which coexists in the electrolytic solution. For instance thallous ion is employed as pilot ion in aqueous media. Vlcek2) suggested lately the half wave potential of potassium ion can be used as reference in any solvent.
The redox-potential, and also the half wave potential, of ion should be affected by its solvation state even in the case where no chemical reaction with supporting electrolytes or with solvent molecules is involved. These circumstances are studied in water-acetonitrile mixtures in the present paper. Thermodynamic analysis of the half-wave potential is only possible in the reversible process, and so the reductions of thallous and cadmium ions are discussed here.
