[01] S. O. Falodun, Department of Science Infrastructure, National Agency for Science and Engineering Infrastructure (NASENI), Idu-Industrial Area, Abuja, Nigeria. [02] S. O. Idris, Department of Chemistry, Faculty of Science, Ahmadu Bello University, Zaria, Nigeria. [03] E. O. Ojo, Department of Science Infrastructure, National Agency for Science and Engineering Infrastructure (NASENI), Idu-Industrial Area, Abuja, Nigeria. [04] J. F. Iyun, Department of Chemistry, Faculty of Science, Ahmadu Bello University, Zaria, Nigeria.

The kinetics of the oxidation of indigo carmine (disodium 3, 3’-dioxobi-indolin-2, 2’-ylidene-5, 5’ disulphonate) with permanganate ion have been studied in aqueous sulphuric acid at 26±1°C, I = 0.25 mol dm^-3 (Na₂SO₄) by monitoring the absorbance of indigo carmine (IC) at 610 nm. The reaction is first order in [IC] and [MnO₄^-] and a stoichiometric mole ratio of IC: MnO₄^- is 1:1. The rate of reaction is independent on changes in ionic strength and added cations did not affect the reaction rate which further supports the effect of changes in ionic strength. The experiment rate law obtained is: Rate = (K+ K""[H⁺]) [IC][MnO₄^-].A plausible mechanism has been proposed on the basis of our experimental results.

Kinetic, Mechanism, Indigo Carmine, Permanganate, Acidic Medium

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