Ion association and solvation behavior of copper sulfate in binary aqueous-methanol mixtures at different temperatures

The specific conductance (κ) of copper sulfate in binary mixtures (methanol-water) with the alcohol mass fractions of 0%, 20% and 40% at different temperatures of (298.15, 303.15, 308.15 and 313.15) K was measured experimentally. The conductivity data have been analyzed using the Fuoss-Shedlovsky conductivity equation. The molar conductance (ΛM), the limiting molar conductance (Λ0), the association constants (KA), the Walden product (Λ0η0), and the standard thermodynamic parameters of association (ΔG°A, ΔH°A and ΔS°A) were calculated and discussed. The results show that, the molar conductance and the limiting molar conductance values were decreased as the relative permittivity of the solvent decreased while, the association constant increased. Also the results show that the values of the molar conductance, the limiting molar conductance and the association constant were increased as the temperature increased indicating that the association process is an endothermic one.