Ion-solvent interactions and ionic association in ethanol solutions

The electrical conductivities of potassium halides in ethanol have been measured at 25°C. The limiting molar conductances, ionic association constants and the closest approach parameter were calculated (Justice method) and compared with existing literature data. An inversion of the anion size dependence of ionic association constants for these solutions was observed. The results are explained by what has been called localized solvolysis, in which both the cation and the anion of the solvent separated ion pair are connected with different parts of the separating solvent molecule by donor-acceptor bonding. A correlation between K_A and protonic affinity of anions was found. Similar literature data for aqueous and non-aqueous solutions are also examined.