Application of polarographic maxima to the determination of kinetic parameters of irreversible reductions

Abstract

Most methods hitherto used for the determination of the kinetic parameters of irreversible reductions (or oxidations) from polarographic data have the disadvantage that surface-active maximum suppressors must be present; these often change the kinetic parameters. In this paper it is suggested that use be made of the strong convection which accompanies a polarographic maximum of the first kind, occuring in the absence of maximum suppressors. For currents up to 15–30% of the diffusion current, concentration polarization has been found to be negligible. For higher currents a simple empirical relation for the concentration polarization has been found, which made it possible to include these data (up to twice the diffusion current) in the determination of the kinetic parameters. In this way, the kinetic parameters for the reduction of bivalent cobalt and manganese in solutions containing lithium or magnesium perchlorate as supporting electrolyte have been determined.