Preferential solvation of silver(I) acetate in water, methanol and their mixtures with dimethyl sulfoxide

TLDR: In this article, the solvent transport number, Δ, of dimethyl sulfoxide and Gibbs solvation energies of silver acetate in binary solvent systems, water and methanol, were determined by employing EMF and solubility measurements.

Abstract: The solvent transport number, Δ, of dimethyl sulfoxide andGibbs solvation energies of silver acetate in the binary solvent systems, water—DMSO and methanol—DMSO, were determined by employingEMF and solubility measurements. While the transfer free energy of the salt increases from water to water—DMSO mixtures (up toX DMSO =0.7) and then decreases, it continuously decreases from methanol to methanol—DMSO mixtures. In both mixed solvents, ΔG° t(Ag+) decreases down to pureDMSO and that of acetate ion increases with increasing composition ofDMSO indicating that silver ion is preferentially solvated byDMSO and acetate ion by water or methanol in these mixtures. The solvent transport numbers, Δ, ofDMSO are positive throughout, passing through a maximum atX DMSO =0.45 (Δ=1.0) in the case of water—DMSO mixtures and atX DMSO =0.25 (Δ=1.8) in methanol—DMSO mixtures. This observation is shown to be in accord with the conclusions arrived at from the transfer energy data of the salt in the two mixtures.