Standard potentials of the silver, silver bromide electrode in tetrahydrofuran and tetrahydrofuran + water mixtures at different temperatures and related thermodynamic quantities

Abstract

The standard potentials of the Ag, AgBr electrode have been determined in tetrahydrofuran (THF) and in nineteen THF + water solvent mixtures from the e.m.f. measurements of the cell Pt|H₂(g, 1 atm)| HBr(m), solvent|AgBr (s)|Ag at intervals of 5 °C from 5 to 45 °C. In solvents of high THF content, where the dielectric constant is small, it was necessary to correct for ion-pair formation. The temperature variation of the standard potential has been utilized to evaluate the standard thermodynamic functions for the cell reaction and the standard thermodynamic quantities for the transfer of HBr from water to the respective solvents. The results are discussed in the light of ion–solvent interactions as well as the structural changes of these solvents.