Conductometric study of ion association of divalent symmetric electrolytes:: II.: MgSO4 in water plus 1,4-dioxane mixtures

Electric conductivities of diluted magnesium Sulfate solutions in binary mixtures of 1,4-dioxane with water were measured covering a solvent composition range up to 50 wt.% of 1,4-dioxane at temperatures from 5 to 35 degrees C. Evaluation of the limiting molar conductivity Lambda(infinity) and the association constant K-A is based on the chemical model of electrolyte solutions, including short-range forces. From the temperature dependence of the limiting molar conductivities Eyring's enthalpy of activation of charge transport was estimated. The standard Gibbs energy, enthalpy and entropy of the ion-pairing process were calculated from the temperature dependence of the ion-association constants. (C) 2006 Elsevier B.V. All rights reserved.