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 (H_2SO_4) 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:Cr_2O^2- _7 ). 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 = k_2[ArCHO][Cr_2O^2- _7], where k_2 = second order rate constant for the reaction. The proposed rate equation for the reaction is: -d[Cr_2O^2- _7]/dt = k_2 [ rCHO] [Cr_2O^2- _7]. The reaction of ArCHO and Cr_2O^2- _7 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.