Theory of electrolytes. Part 1.—The model of polarisable spheres

Abstract

A new theory of electrolyte solutions is described which is based on the Debye–Hückel model, modified to allow for mutual polarisation of ions. From a general solutions of the linearised Poisson–Boltzmann equation, an expression is derived for the activity coefficient of a central polarised ion in an ionic atmosphere of non-spherical symmetry. The expression reduces to the Debye–Hückel limiting laws at infinite dilution. The characteristic shapes of activity coefficient curves are realistically represented by the theory up to moderately high concentrations. The status of the various equations involved in the Debye–Hückel theory is discussed.