Kinetics and Mechanism of Reduction of Hexacyanoferrate(III) by Sodium Tetrahydroborate

A kinetic investigation of the reduction of hexacyanoferrate(III) by sodium tetrahydroborate in buffered aqueous solution has been carried out. The rate of the reaction is proportional to the concentration of both, tetrahydroborate and hydrogen ions. The effect of the addition of some inorganic salts has been studied. The temperature has been varied, and the Arrhenius parameters have been evaluated. The rate of hydrolysis of tetrahydroborate has been separately studied. It has been observed that the activation energies for both the reactions—the reduction of hexacyanoferrate(III) and the hydrolysis of tetrahydroborate—are equal. A plausible mechanism for the reduction of hexacyanoferrate(III) has been proposed.