Diffusivity of chromium salts and alums in aqueous solutions

The diffusion coefficients of potassium aluminium sulphate, ferric ammonium sulphate, chromium potassium sulphate and chromium sulphate were determined using the porous disc technique. For all salts studied linear relations were found between the diffusion coefficient and the square root of the salt concentration: The effect of temperature on the diffusion coefficient of the salts was studied. The data were found to fit the Arrhenius equation. The activation energies for the diffusion of potash alum, ferric alum, chrome alum and chromium sulphate were found to be 1.8, 7.4, 2.8 and 3.4 kcal/mol respectively.