Investigation of Ion-Pair Association for KCl Electrolyte in Methanol Based on Conductance Method

The conductometry is the analytical method used both in research laboratories as well as in industry. The electric conductivity is one of the most important properties of electrolyte solution [1]. The theoretical assumption of this method is the fact that the electrolytic conductivity is the result of the motion of anions and cations [2].In this research, using the Debye-Huckel limiting law and by calculating the appropriate amount of parameter, AD-H, in the methanol and water solvent, the values of the mean activity coefficients for KCl at each concentration were calculated. Then, based on the Fuoss Approximation, the dissociation constant, and using the law of mass action and activities, the association constant, all as a function of concentration, along with the limiting conduction for KCl electrolyte in methanol were determined by conductimetric method, and compared with their corresponding values in aqueous solvent.According to the results, it was found that the formation of ion-pair for KCl in water is essentially zero, but with decrease of Dielectric constant of solvent, the degree of ion-pair formation also increases with concentration.