Document Type
Original Article
Subject Areas
Chemistry
Keywords
Kinetics; Oxidation; L-ascorbic acid; Chromium (VI)
Abstract
The kinetics of oxidation of L-ascorbic acid by potassium chromate was studied as a function of pH, L-ascorbic acid concentration and temperature using the spectrophotometric technique. The rate of reaction is first order with respect to the concentration of each reactant and increases as [H+] increases. The kinetic data indicate involvement of the monoprotonated ascorbate species (HA-) in the redox process. A mechanism involving the formation of chromium (VI)- ascorbate intermediate is a rate-determining step followed by a redox step was suggested. The activation enthalpy and activation entropy changes for the reaction have been calculated to be ΔH*= 69 kJmol-1 and ΔS*= -209 JK-1 mol-1, respectively.
How to Cite This Article
MANSOUR, MOHAMED
(2010)
"KINETICS AND MECHANISM OF OXIDATION OF L-ASCORBIC ACID BY CHROMIUM (VI),"
Al-Azhar Bulletin of Science: Vol. 21:
Iss.
1, Article 17.
DOI: https://doi.org/10.21608/absb.2010.7344