Kinetics and mechanism of redox reaction of neutral red and bromate ion in aqueous acidic medium

The kinetics and mechanism of redox reaction of neu tral red, NR, and bromate ion, BrO , was studied in aqueous hydrochloric acid medium under pseudo-first o der conditions at 25 ± 1°C, [H ] = 2.0 10 mol dm, I = 0.5 mol dm (NaCl) and λmax = 525 nm. The reaction was first order with respec t to both [NR ] and [BrO ], and second order with respect to [H ]. The rate of the reaction displayed a positive Bro nsted-Debye salt effect. There was no evidence of the formation of an intermediate complex of significant stabilit y and free radicals were probably not present in the reac tion. The observations above, coupled with the resu lt of Michaelis-Menten plot suggests an outer sphere mech anism for the reaction. The reaction obeys the rate equation: . A plausible mechanism has been proposed for the reaction.