Conductometric study of some alkali metal halides in (dimethyl sulfoxide + acetonitrile) at T = 298.15 K

Electrolytic conductivities of some alkali metal halides, MX (M+ = Li+, Na+, and K+; X− = Cl−, Br−, and I−), NaBPh4 and Bu4NBr have been investigated in (20, 40, and 60) mass% {dimethyl sulfoxide (DMSO) in DMSO + acetonitrile} at T = 298.15 K. The conductance results have been analyzed by the Fuoss-conductance-concentration equation in terms of the limiting molar conductance Λ° the association constant KA and the association diameter R. The ionic contributions to the limiting molar conductance have been estimated using Bu4NBPh4 as the “reference electrolyte”. The association constant KA tends to increase in the order mass percent 20 < 40 < 60 DMSO in (DMSO + acetonitrile) which is explained by the thermodynamic parameter ΔG° and Walden product Λ°η. The results have been interpreted in terms of ion–solvent interactions and structural changes in the mixed solvents.