Abstract
The diffusion coefficients of CuCl2, FeCl3, and Fe2(SO4)3 in acidic aqueous solutions were measured at 298 K using a diaphragm-cell method. Also the diffusion coefficients of CuCl2 in water were determined at the same temperature. The data obtained are listed as a function of the molar concentrations of the solutes. The diffusion coefficients of CuCl2 in water are larger than those of CuSO4. The concentration dependency of the diffusion coefficients for CuCl2 in water could be explained in terms of the changes in the mean activity coefficients of CuCl2 and in the viscosity of the solutions. The diffusion coefficients of CuCl2 in aqueous HCl solutions are larger than those of FeCl3. The presence of HCl has a significant influence on the diffusion of CuCl2 and FeCl3, and it decreases their diffusion coefficients. On the other hand, the diffusion coefficients of CuSO4 in aqueous H2SO4 solutions are larger than those of Fe2(SO4)3. However, the presence of H2SO4 have no significant effect on the diffusion coefficients of Fe2(SO4)3. The effect of HCl and H2SO4 on the diffusion coefficients of CuCl2, FeCl3 and Fe2(SO4)3 were discussed based on the predominant diffusing species and the diffusion potential due to the H+ ions migration.
