A conductance investigation of HCl in aqueous solutions of tetrahydrofuran,dimethoxyethane and dioxane

Conductance of dilute solutions of HCl in water-tetrahydrofuran (THF), water-dioxane and water-dimethoxyethane (DME) were measured and the data processed using the Justice-Ebeling equation to evaluate the limiting conductance _O, the association constant K_A and the apparent distance of closest approach a'. The Friedman-Rasaiah Gurney cosphere overlap term d_+–/kT was calculated from a' values and illustrates the different solvation pattern of dioxane compared to that found for THF and DME. It would appear that dioxane can solvate cations more strongly due to its ability to form a boat configuration around a cation. The association constants are reasonably reproduced by the Bjerrum equation using realistic molecular dimensions of the ions involved for the distance of closest approach. The limiting conductance in the mixtures illustrates clearly the different mechanism for proton conductance compared to that for the cesium ion. The dielectric constants, viscosities and densities of the solvent mixtures were measured and are reported. The lowest dielectric constant for each type of solvent mixture was about 10.