Effects of Acethydroxamic Acid on Kinetic of Reaction Between Hydroxylamine and Fe(Ⅲ)

The kinetic of the reaction between hydroxylamine and Fe(Ⅲ) in nitric acid solution was studied by spectrophotometry. The apparent rate equation may be expressed as follows:
-dc(Fe(Ⅲ))/dt=k•c^0.56(Fe(Ⅲ))•c^0.88(HAN)
The apparent rate constant is =-(4.08±0.15)×10^-4 (mol/L)^-0.44•s^-1. The effects of acethydroxamic acid on the reaction were also studied. The apparent rate equation is converted into:
-dc(Fe(Ⅲ))/dt=-(2.83×10^-4-536c³(AHA))•c^0.76(Fe(Ⅲ))•c^0.60(HAN)
The apparent rate constant decreases with the increase of the concentration of AHA and is linearly related to the cubic of the concentration of AHA. The effect of the concentration of Fe(Ⅲ) on the apparent rate increases, while that of the concentration of HAN decreases.