Full Paper Kinetics and mechanism of electron transfer reaction between tetraoxoiodate(VII) ion and 1,3-benzenediol Sulaiman O.Idris 1 *, Nnamdi N.Nwanze 1 , Johnson F.Iyun 1 , Pius O.Ukoha 2 1 Department of Chemistry Ahmadu Bello University, Zaria, (NIGERIA) 2 Department of Pure and Applied Chemistry, University of Nigeria, Nnsukka, (NIGERIA) E-mail : alhajisoidris@yahoo.com Received: 13 th September, 2010 ; Accepted: 23 rd September, 2010 An Indian Journal Trade Science Inc. Volume 6 Issue 1 PCAIJ, 6(1), 2011 [5-8] Physical CHEMISTRY Physical CHEMISTRY ISSN : 0974 - 7524 ABSTRACT The stoichiometry, kinetics and mechanism of the electron transfer reaction between tetraoxoiodate (VII) ion and 1,3  benzenediol have been investigated at 30–0.5 o C. The reaction follows the rate law:   ]) IO [ R H ( ]) H [ k ' K k ( dt ] IO [ d 4 2 3 1 4       where H 2 R = 1,3-benzenediol. The rate of the reaction is indepen- dent of change in ionic strength of the reaction medium in the range of 0.05  I  0.4 mol dm -3 . On the basis of the result obtained from Michaelis-Menten plot, outersphere mechanistic pathway is proposed for this reaction.  2011 Trade Science Inc. - INDIA INTRODUCTION Several studies addressing the dynamics of the elec- tron transfer reaction of benzenediols with a wide range of oxidants have been reported [1-13] . These reactions have shown a lot complexities both in terms of acid dependencies and the products [1,6,9] . For example, Iyun [6] reported acid dependence and acid indepen- dence in the oxidation of 1,2benzenediol by BrO 3 - and MnO 4 - respectively in aqueous acidic medium and free radicals in both systems. In addition, the desire to gain adequate knowledge on the redox pattern of IO 4 - also heightened our inter- est in investigating its reaction with 1,3benzenediol. Most of its reactions with both organic and inorganic substrates are thought to occur by both inner and outersphere mechanisms [14-19] . It is our hope that the data obtained in this investigation will assist in providing more information on the complexities that attend the reaction of IO 4 - . EXPERIMENTAL The purity of 1,3benzenediol (Hopkins & Will- iams) hereafter referred to as H 2 R was confirmed by it melting point (110C). Fresh solutions of NaIO 4 (BDH) and H 2 R were prepared daily before use. Standard solution of HCl was prepared as described in the lit- erature [20] . All other chemicals were of analytical re- agent grade. All solutions were prepared with distilled water. Stoichiometry This was determined by spectrophotometric titra- tion using condition identical to those described ear- lier [6-13] . Absorbances of the product were measured