Activity coefficients of individual ions

Abstract

Abstract Existing methods for the estimation of the primary medium effect for individual ions are critically reviewed and an improved method for its estimation is developed. By this method the primary medium effect of the hydrogen ion has been determined for the transfer from water to methanol‐water mixtures and methanol. The medium effect of the alkali and the halide ions are then also known. The accuracy of the values so obtained for the individual ions is of the same order as the accuracy of experimentally determined values for electroneutral combinations of ions.