The Kinetic Behaviour of Mn+7/H+ Ions Towards Mannose Molecule

Abstract

The spectrophotometric method monitored the uncatalysed redox reaction between Mn+7/H+ ions and mannose sugar molecules kinetically at constant ionic strength maintained using potassium nitrate (KNO3). The kinetic study showed that the reaction was pseudo-first order concerning Mn+7 and mannose, and the rate of reaction increases by increasing the concentration of Mn+7, mannose and H+ and increasing temperature. The reaction rate was enhanced by 3 × 10–4m of Mn+7 concentration, and the oxidation with Mn+7 was faster using 2 × 10–2m of mannose and 5 × 10–1m of H+. The temperature dependence was carried out under fixed experimental conditions, from which the activation energy of the reaction (Ea) in KJ.mol–1 was found to be 61.1, and the frequency factor (A) in sec–1 was 10.52 × 105 other physical functions, namely, the free energy change (∆G) in KJ.mol–1 and the entropy change (∆S) in J.K –1 were also calculated at different temperatures. Qualitative analysis of the reaction products revealed the formation of formic acid. A rate law was derived from the proposed mechanism, which agreed well with experimental kinetics.