On the excess thermodynamic properties of aqueous electrolyte solutions—I

A new approximate formulation describing the electrostatic contribution to the excess free energy of electrolyte solutions is presented. The final equation contains only one parameter and reduces to the Debye-Huckel limiting law at low enough concentrations. It represents the experimental data nicely for the series of alkali metal halides out to quite high concentration, and clarifies certain difficulties in interpretation of solvent isotope effect data with extended theories now in widespread use.