Standard Gibbs free energies of transfer of NaCl and KCl from water to mixtures of the four isomers of butyl alcohol with water. The use of ion-selective electrodes to study the thermodynamics of solutions

Abstract

Measurements have been made on NaCl and KCl in water and in mixtures of water with the four isomers of butyl alcohol using the following cell, which has no liquid junction and which consists of ion-selective electrodes: cation(M); responsive glass or ion-selective electrode [graphic ommitted]. The standard Gibbs free energies of transfer of NaCl and KCl from water to mixtures of water with the four isomers of butyl alcohol were calculated from cell potentials. This paper compares measurements of ΔE^°_t and G^°_t using ion-selective electrodes with those obtained from amalgam cells. The results obtained using ion-selective electrodes are reliable, and the differences between ΔG^°_t of NaCl and KCl from water to butyl alcohol–water mixtures are very small. ΔG^°_t is proportional to the amount of butanol present over the experimental concentration range.