ION-SOLVENT INTERACTIONS OF SILVER(I) SALTS IN WATER-DMSO MIXTURES FROM CONDUCTANCE MEASUREMENTS

The conductances of silver(I) perchlorate, nitrate and bromate have been determined in water-dimethylsulfoxide (DMSO) mixtures at 30-degrees-C over the complete range of solvent compositions. The data were analyzed by the 1980 Fuoss equation and the limiting molar conductances (LAMBDA-0) and association constants (K(A)) of the salts were evaluated at all compositions. The LAMBDA-0 values have been split into their ionic values and the ionic Walden products of all the ions were calculated using the transference number data derived from a concentration cell with transference. The initial increase of the Walden product of silver ion up to 20 wt% DMSO and its subsequent decrease beyond this composition with addition of DMSO, indicates that it is preferentially solvated by water at high compositions of water and subsequently by DMSO. For anions, the Walden products vary in a complex manner and seem to be strongly influenced by solvent-solvent interactions.