The decomposition of \(H _2 O _2\) in alkaline medium, in presence of \(I ^{-}\)ions occurs as follows :
\(2 H_2 O_2 \xrightarrow{I^{-}, \text {allaline medium }} 2 H_2 O+O_2\)
If the reaction occurs in the following two steps:
Step 1: \(H _2 O _2+ I ^{-} \xrightarrow{\text { Slow }} H _2 O + IO ^{-}\)
Step 2 : \(H _2 O _2+ IO ^{-} \xrightarrow{\text { Fast }} H _2 O + I ^{-}+ O _2\)
The correct rate law expression for the reaction is :

1. A \(r=k\left[ H _2 O _2\right]^2\left[I^{-}\right]\)
2. B \(r=k\left[ H _2 O _2\right]\left[I^{-}\right]\)
3. C \(r=k\left[ H _2 O _2\right]\left[1 O ^{-}\right]\)
4. D \(r=k\left[ H _2 O _2\right]^2\left[ I ^{-}\right]\left[ OH ^{-}\right]\)