Electron Transfer Reaction between Naphthol Green B and Permanganate Ion in Aqueous Acid

The redox reaction between naphthol green B (NGB3-) and permanganate ion has been studied in tetraoxosulphate(VI) acid medium at an ionic strength, I = 0.50 mol dm-3 (Na2SO4), [H+] = 4 × 10-4mol dm-3 (H2SO4), T = 21 ± 1oC and λ = 700 nm. The redox reaction displayed a stoichiometry of 2:1. The reaction shows a first order dependence on [oxidant] and [reductant]. Study on the effect of ionic strength on the rate of the reaction shows that the rate of the reaction obeyed positive Bronsted - Debye salt effect; implying that the activated complex is composed of reactants of similar charges. Increased in hydrogen ion did not affect the rate of the reaction. The overall reaction conforms to the rate law: Addition of acrylonitrile to a partially reacted mixture in the presence of excess methanol did not lead to gel formation. Added cations and anions had no effect on the rate of the reaction. Results of the Michaelis – Menten’s plot gave no evidence of intermediate complex formation during the course of the reaction. Based on the results obtained, the reaction is probably proceeding through the inner-sphere mechanistic pathway.