Studies in Isodielectric Solvents: Part 1—Standard Potentials of the Silver-Silver Chloride Electrode in the Acetonitrile + Ethylene Glycol Solvent System at 25'C

Abstract

Standard potentials (E°) of the silver-silver chloride electrode have been determined at 25'C in ethylene glycol and in its approximately isodielcctric mixtures with 20,40 and 60 wt. % acetonitrile, from e.m.f. measurements performed on the cell Pt, H2(g, 1 atm.)/HCl(m), solvent/Ag-AgCl. Standard free energies of transfer (AG®), of HC1 at 25°C from ethylene glycol to acetonitrile + ethylene glycol mixtures, obtained from these measurements have been interpreted in terms of the acid-base nature of the solvents. Comparison of the AG®-composition profile with those of other isodielectric solvent systems has been used to confirm the idea of ion desolvation caused by dipolar aprotic solvents like acetonitrile.