Free Convection in Micro-electrolysis Cells

Abstract

O'Brien and Rosenfield¹ have already presented conclusions concerning the interpretation of interference fringe patterns obtained in micro-electrodeposition cells. It was suggested that the second wave (Figs. 1 and 2c) could only be satisfactorily explained as a refractive index change resulting from dissociation of ion-pairs. Interferograms of solutions of salts in which logK dissociation was of the order of 3 (CuSO₄ and ZnSO₄) were compared with those of solutions the K dissociation of which was known to be as large as AgClO₄. This comparison was augmented by further comparisons with solutions where the cation formed a stable aquo-complex, and hence it was assumed that at least one water molecule separated the cation and anion as in NiSO₄. It was assumed that the effect on refractive index of dissociation of an ion-pair in such a solution would be very small and probably negligible. The second wave was either absent or very small in these two latter types of solution.