Determination of Activity Coefficients for Cesium Chloride in Methanol−Water and Ethanol−Water Mixed Solvents by Electromotive Force Measurements at 298.15 K

Abstract

Activity coefficients for CsCl in different methanol−water and ethanol−water mixed solvents were determined at 298.15 K by electromotive force (EMF) measurements of the cell: Cs-ISE|CsCl (m), alcohol (Y), H2O (100 − Y)|Ag|AgCl. The cesium ion-selective electrode (Cs-ISE) and the Ag|AgCl electrode used in this work were made in this laboratory and had good Nernstian response. The experimental data were calculated using the Pitzer model. Standard cell potentials and Pitzer parameters were obtained. From these, mean activity coefficients of CsCl, osmotic coefficients of the mixtures, standard Gibbs free energies of transference of CsCl from water to methanol−water or ethanol−water mixtures, and the corresponding medium effects were calculated.