The Electrolytic conductance of sodium and barium dithionates in dilute aqueous solutions

Abstract

Precise measurements of electrolytic conductance of 2:2 electrolytes have been restricted largely to the sulphates. These all showed a strong tendency towards association in aqueous solution. Recently a series of investigations Atkinson, J.A.C.S., 83 (1961) 1570, 3759, 4367, Atkinson, J.P.C., 67 (1963) 1881. has been carried out on the metal salts of large di- and tri-valent organic anions, usually containing sulphonate groups, e.g. benzene disulphonate. In many cases the results could be fitted by the extended Fuoss-Onsager theory without any allowance for association. The concept behind using such ions was the splitting of the -2 charge on the S04 = ion into two -1 charges on each of sulphonate groups, separated by the inert organic framework. This, Atkinson says, would be expected to reduce "the short range forces promoting ion association", while maintaining the basic properties of a divalent ion, since the separation of the two charges would be small compared with the radius of the ionic atmosphere at the concentration range of interest.