Ionic Self-Diffusion in Aqueous Solutions

2 Ionic Self-Diffusion in Aqueous Solutions The inherent movement of ions in the absence of an external field is their self-diffusion, but a directional concentration gradient at finite concentration (a gradient of chemical potentials) causes directional diffusion of ions. The limiting ionic self-diffusion coefficients are generally obtained from the limiting conductivities 

The values of the limiting diffusion coefficient, D of aqueous ions of the order of 10 m s , at 25°C are shown in Table 2.11. The self-diffusion coefficients increase with increasing temperatures and a fivefold increase in aqueous solutions from 0 to 100°C has been noted. This is mainly because the viscosity of the solvent diminishes in this direction (Table 3.7). 

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