Conductometric study of ion association of divalent symmetric electrolytes:: I.: CoSO4, NiSO4,CoSO4 and ZnSO4 in water

Electric conductivities of cobalt, nickel, copper and zinc sulfate solutions in water were measured from 5 to 35 degrees C (steps of 5 degrees C) in the concentration range 10(-4) < c/(mol dm(-3)) < 4x10(-3). Data analysis, based on the chemical model of electrolyte solutions including short-range interactions, yields the limiting molar conductivity Lambda(infinity) and the association constant K-A. The standard Gibbs energy, enthalpy and entropy of the ion-pairing process were calculated from the temperature dependence of the ion-association constants. (c) 2004 Elsevier B.V. All rights reserved.