Year: 1985
Type: article
Abstract: The equivalent conductivity at infinite dilution of an inorganic acid and its salt were compared in mixtures of water with two aprotic solvents (acetonitrile and tetrahydrofuran). The variation of the ratio of equivalent conductivities with solvent composition reflects directly the anomalous conductivity of , all other factors such as the changes in viscosity and dielectric friction being automatically compensated. The anomalous conductivity of the proton is not observed until the concentration of water exceeds ca. 10 volume percent which corresponds to a mole fraction of 0.24. When plotted as a function of the mole fraction of water, the ratio of equivalent conductivities at infinite dilution is almost the same for mixtures of water with AN and with THF, indicating that the aprotic solvent acts only as a diluent, increasing the distance between water molecules and destroying short‐range order which may exist in water. When the same ratio is plotted as a function of the average distance between water molecules, it is found that hopping can no longer occur to a significant extent when the average distance is more than 2.2 times its value in pure water. A similar effect was observed recently in studies of the conductivity of Br − in liquid bromine and its mixtures with nitrobenzene. The Walden product for the proton decreases significantly upon the addition of relatively small amounts of the aprotic solvent, and can decrease by a factor of two when the mole fraction of water decreases from unity to . Further studies in mixed solvents could shed light on the mechanism of proton conductivity in protic solvents and possibly on the structure of water.
DOI: 10.1149/1.2114310
Authors: Z. Stein, E. Gileadi
Institution: Tel Aviv University
Language: English
Subfield: Fluid Flow and Transfer Processes
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2019501929