Bromate ion oxidation of Pyrocatechol Violet in aqueous hydrochloric acid: Kinetics and mechanism 

ByAdetoro A., Iyun J. F. and Idris S.O. 

ABSTRACT

The  kinetics of the oxidation of pyrocatechol violet hereafter (refered to PCVH) by bromate ions has been carried out in aqueous hydrochloric acid medium at ?max of 440nm, T = 26 ± 0.1oC, I = 0.50 mol dm-3 (NaCl) and [H+] = 0.10 mol dm-3 (HCl). The  reaction is first order with respect to oxidant and reductant concentration. The reaction obeyed a general rate law  

formula

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with k2 = 2.74 dm-3mol-1s-1. The reaction rate is affected by changes in the concentration of hydrogen ions and in the ionic strength of reaction medium. Added cation and anion inhibited the reaction rate respectively. The results of spectroscopic and kinetic investigation show that no intermediate complex is formed in the course of this reaction. 

Key words: Pyrocatechol violet, bromate ion, kinetics, mechanism.

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