Electrical Conductivity in Dimethyl Sulfoxide + Potassium Iodide Solutions at Different Concentrations and Temperatures

The direct current conductivity of DMSO + KI solutions was determined with the use of the impedance spectroscopy. The measurements were performed in the whole solubility range of KI and in the temperature range from (293.15 to 323.15) K. The limiting molar conductivities Λo(T) and λI–o(T), as well as the constant KA of ionic association, K+ + I–, were determined at different temperatures with the use of the Fuoss-Onsager method. The obtained data on KA, together with the literature data referred to the K+ + I– association in different solvents, allowed us to formulate an empirical dependence of KA on the molecular dipolar polarizability of the solvent used, KA ∝ exp(−μi2), where μi is the dipole moment of the molecules of ith solvent.