The kinetics and mechanism of the reduction of Co2(OH)2(C2O4)4 4- by Nitrous acid has been investigated in aqueous perchloric acid medium. The reaction obeys second order kinetics with the rate law;
−d[Co2(OH)2(C2O4)4 4-]/dt = k2[Co2(OH)2(C2O4)4 4-][ HNO2] Where k2 = (9.99 ± 0.36) x 10-4 dm3mol-1 s-1
The reaction is acid-independent in the [H+] range studied, suggesting that protonation occurs after the electron-transfer step. Free radicals are important intermediate in this redox process and the results are discussed in terms of outer-sphere mechanism.