Cluster theory applied to aqueous (2:2) electrolytes over a wide concentration range. Osmotic coefficients, association and redissociation

Abstract

The cluster theory recently derived by Tani and Henderson has been extended to the unrestricted primitive model limiting the number of ions in the clusters to a pair. In this way it was possible to describe the osmotic coefficients of MSO₄ aqueous solutions at 298 K up to 3 mol dm^–3 employing a single freely adjustable parameter, the cation diameter σ₊. This modified cluster theory is capable of accounting for the redissociation of associated electrolytes observed at higher concentrations and is consequently a very versatile tool to describe the behaviour of electrolytes over wide concentration and/or temperature ranges.