Surface Tension of Ionic Solutions

Abstract

As an illustration of the molecular theory of surface regions, the singlet and pair distribution functions are evaluated for very dilute ionic solutions. When they are substituted into the statistical mechanical formulas for surface tension, expressions are obtained for the increase in surface tension over that of the pure solvent. The results of the theory are in better agreement with experiment than the earlier calculation of Onsager and Samaras, which was based on integration of the Gibbs adsorptionequation. Finally, the distribution function approach is simply related to Mayer's recent virial coefficient theory for strong electrolyte solutions.