Kinetics of the Redox Reaction of Benzaldehyde and Dichromate Ions in Aqueous Acidic Medium

The kinetics of the redox reaction of benzaldehyde and dichromate ions in aqueous acidic media was determined. The data obtained was carried out at wavelength, λ = 420 nm, acid (H₂SO₄) was used to catalyze the reaction, ([H⁺] = 0.1 mol dm^-3) and temperature = 35 ± 0.5 °C. The stoichiometry of the reaction using the mole ratio method was found to be 5:1 (ArCHO:Cr₂O₇^2-). The rate showed first order each with respect to the reductant and oxidant and second order overall. The overall rate law was predicted as; Rate = k₂[ArCHO][Cr₂O₇^2-], where k₂ = second order rate constant for the reaction. The proposed rate equation for the reaction is: -d[Cr₂O₇^2-]/dt = k₂ [ rCHO] [Cr₂O₇^2-]. The reaction of ArCHO and Cr₂O₇^2- was catalysed by H⁺ through one pathway, the acid pathway. Michaelis-Menten plot showed a positive slope with no significant intercept and the absence of intermediate complex formation suggesting a spontaneous reaction.