Authors:C. Robert Dennis, I. Potgieter, and S. Basson
The kinetics of the oxidation of hydroxide ions by octacyanomolybdate(V) ions has been studied in the [OH−] range between 0.5 and 4.0 mol dm−3. The reaction displays first-order kinetics in both [Mo(CN)83−] and [OH−] and is consistent with the rate law R = k [Mo(CN)83−] [OH−]. From the Brønsted-Bjerrum equation, it was established that the activated complex is formed by the ions Mo(CN)83− and OH−. A reaction mechanism is proposed for the reaction with a rate constant of 1.13 ± 0.03 × 10−2 dm3 mol−1 s−1, activation enthalpy, ΔH#, of 20.1 ± 09 kJ mol−1 and activation entropy, ΔS*, of −213 ± 3 J K−1 mol−1.
Authors:C. Robert Dennis, I. M. Potgieter, and S. S. Basson
The kinetics of the oxidation of formaldehyde by octacyanomolybdate(V) ions has been studied in aqueous alkaline medium. A formaldehyde-dependent and -independent reaction has been observed. The HCHO-dependent reaction displays first order kinetics in [Mo(CN)83−], [HCHO], [OH−] and alkali metal ion catalysis was observed. The rate law is consistent with: Activation parameters for both the formaldehyde-dependent and -independent reaction have been obtained. The activation parameters for the HCHO-independent reaction provide evidence for the identification of the reaction. A reaction mechanism is proposed.