ABSTRACT:The kinetics of oxidative decolorization of acid orange 10 (AO10) by chloramine-B and bromamine-B in HClO 4 medium has been investigated spectrophotometrically (λ max = 475 nm) at 298 K. Kinetic runs were performed under pseudo first-order conditions of [oxidant] [HClO 4 ]. Stoichiometry of the reaction was found to be 1:1 and the oxidation products were identified. The reaction was studied at different temperatures and various activation parameters have been computed. Effects of p-toluenesulfonamide, halide ions, ionic strength and dielectric constant of the medium have been investigated. Reaction mixture fails to induce polymerization of acrylonitrile. The rate of oxidation of AO10 is about two-fold faster with BAB as compared to CAB. This may be attributed to the difference in electrophilicities of Cl + and Br + ions and also the van der Waal's radii of chlorine and bromine. Plausible mechanism and related rate law have been deliberated for the observed kinetics.