Electrolyte-diffusion of Co(NO₃)₂ in agar gel medium

In the present study, the electrolyte diffusion of Co(NO₃)₂ in 1 % agar gel using ⁶⁰Co (t_1/2 = 5.27y) as a tracer with a zone-diffusion technique is reported in the concentration range of 10^-5 to 0.25 M at (25 ± 0.1) deg C. The observed deviations between theoretical and experimental diffusion coefficients have been attributed on the basis of ion-ion, ion-gel, and ion-water interactions which are not considered while formulating the Onsager-Fuoss theory. Activation energies for the electrolyte diffusion of Co(NO₃)₂ in 1 % agar gel is found to decrease with an increase in the electrolyte concentration. The decrease in the obstruction effect expressed in terms of α is accounted for on the basis of competitive hydration between the ions and agar molecules. (author)