Thermodynamic and kinetic studies on oxidation of pyrogallol red by hydrogen peroxide in the absence and presence of molybdenum(VI)

The oxidation of pyrogallol red (PGR) by hydrogen peroxide has been studied both in the absence and presence of molybdenum(VI) at pH of 7.0 by spectrophotometric detection. The reaction rate was studied with a fix-time method from 0.5 to 4.5 min. The effect of reagents concentration, ionic strength and temperature was studied to give the optimum conditions. At the optimizing conditions the rate constant, energy and entropy of activation and frequency factor have been calculated using the Arrhenius and Eyring plots.