Kinetics of oxidation of bromide ions by aquacerium(IV) ions in aqueous perchlorate media

Abstract

The kinetics of the rapid oxidation of bromide ions by the aquacerium(IV) ion have been investigated using stopped-flow spectrophotometry. The rate is found to be first order in [Ce^IV_aq], second order in [Br^–] and second order in [H⁺]. These reaction orders in [Br^–] and [H⁺] can only be explained by the oxidation proceeding through intermediate complexes, and possible rate determining steps are explored. These kinetics are discussed in relation to the mechanisms found for the oxidation of other ligands by Ce^IV_aq and compared with oxidations by other aqua-cations.