Investigations of the Redox Reactions of Potassium Trisoxalatoferrate(III) with Perchlorate Ion in Acidic Medium: A Kinetic Approach
Ogori, B. O. *
Department of Chemistry, F.C.E. Pankshin, Plateau State, Nigeria.
Lohdip, Y. N.
Department of Chemistry, University of Jos, Jos, Nigeria.
Gongden, J. J.
Department of Chemistry, University of Jos, Jos, Nigeria.
Apagu, N. T.
Department of Chemistry, F.C.E. Pankshin, Plateau State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
This study investigated the redox reactions of potassium trisoxalatoferrate(III) trihydrate with perchlorate ion in acid medium. The stoichiometry of the reaction determined by the mole ratio method were observed to be 1:2. The rate of the reaction showed two parallel pathways. The kinetic results showed first order dependence with respect to both oxidant and reductant concentrations and the experimental data are consistent with the rate law:
\(\frac{-d\left[\mathrm{Fe}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3{ }^{{ }^{3-}}\right]}{d t}=\left\{a+b\left[\mathrm{H}^{+}\right]\right\}\left[\mathrm{Fe}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3{ }^{3-}\right]\left[\mathrm{ClO}_4^{-}\right]\)where \(\mathrm{a}=0.07 \mathrm{~s}^{-1}\) and \(\mathrm{b}=0.74 \mathrm{dm}^6 \mathrm{~mol}^{-2}\). The effect of added species (Zn2+, Mg2+ CH3COO-, I-, and NO3-) on the rates of the reaction and other kinetic evidence suggest that the reactions occurred by the outer-sphere mechanism. The findings from the study has established baseline kinetic data for the redox reaction of potassium trisoxalatoferrate(III) trihydrate with ClO4- and plausible mechanisms have also been proposed for the reaction system.
Keywords: Kinetics, trisoxalato complexes, outer-sphere mechanism