Degree of Dissociation of Bi-bivalent Salts in very Dilute Aqueous Solution

Abstract

THE measurements carried out by Shedlovsky¹ of the equivalent conductivities of solutions of uni-univalent salts in aqueous solution are in good agreement at high dilution with the theoretical equation developed by Onsager², but such measurements of conductivities of bi-bivalent salts as are available indicate deviations from theory beyond the magnitude of possible errors of experiment. The equivalent conductivity in this case diminishes far more rapidly with rise of concentration than is predicted by Onsager's equation. Attention has been directed to this point by Davies³, who calculates dissociation constants for this class of electrolyte. On the other hand, La Mer and collaborators⁴ take the view that bi-bivalent electrolytes are completely dissociated in dilute aqueous solution, and support their contention by measurements of activity coefficients of zinc sulphate and cadmium sulphate.