Limiting partial molar volumes of electrolytes in dimethyl sulfoxide–water mixtures at 298.15 K

Abstract

Limiting partial molar volumes of electrolytes in several water-dimethyl sulfoxide mixtures, up to xDMSO= 0.1587, have been determined from density measurements at 298.15 K. A reference electrolyte assumption (TATB) has been used in order to obtain single-ion partial molar volumes of transfer from water to DMSO–water mixtures. The influence of DMSO on ΔtV′0i of alkali metals and halide ions is negligible in the highly water-rich region (up to xDMSO≈ 0.04) except for the I– ion. However, when the DMSO composition is greater than xDMSO≈ 0.04, the variation of ΔtV′0i for alkali metals is the reverse to that of halide ions. The results are discussed on the basis of ion–solvent and solvent–solvent interactions using Conway's model.