Kinetics and Mechanism of Oxidation of Tellurium(IV) by Alkaline Diperiodatonickelate(IV)

Abstract The kinetics of oxidation of tellurium(IV) (Te(IV)) by diperiodatonickelate(IV) (DPN) in aqueous alkaline medium has been studied spectrophotometrically. The reaction exhibits first order in [DPN] and fractional order both in [Te(IV)] and [OH-]. Periodate has a retarding effect on the rate of reaction. Effects of added products, ionic strength and dielectric constant of the reaction medium have been investigated. A mechanism involving the monoperiodatonickelate( IV) (MPN) as the reactive species of the oxidant has been proposed. The constants involved in the mechanism are obtained. There is a good agreement between the observed and calculated rate constants. The activation parameters are computed with respect to the slow step of the mechanism.