KINETICS OF REDUCTION OF SILVER(I) GELATIN COMPLEX IN AQUEOUS ALKALINE-SOLUTION

The kinetics of reduction of silver (I)-gelatin complex by ascorbic ac id and hydrazine has been studied spectrophotometrically with trace co ncentration of reducing agents in alkaline medium with low ionic stren gth (<0.1 M) in the temperature range 15-degrees-41-degrees-C. The red uction is first order each in both the reactants with an inverse first order dependence on [H+] for ascorbic acid oxidation and shows an alm ost zero order dependence on [H+] for hydrazine oxidation. The activat ion parameters are found to be DELTAH(not-equal) = 20.67 +/- 2.5 kJ mo l-1, and DELTAS(not-equal) = -24.1 +/- 4.5 J K-1 mol-1 for the reducti on of the complex by ascorbic acid while those for the reduction of si lver (I)-gelatin complex by hydrazine were found to be 23.72 +/- 2.05 kJ mol-1 and 12.3 +/- 2.5 JK-1 mol-1, respectively. A tentative mechan ism consistent with the kinetics is discussed.