Consider the decomposition reaction :
`2H_2O_2 overset(OH^(-)//I^-)to 2H_2O + O_2`
This reaction takes place in two steps as given below :
Step 1. `H_2O_2 + I^(-) to H_2O + IO^(-)` (slow)
Step 2. `H_2O_2 +IO^(-) to H_2O + I^(-) + O_2` (fast)
Determine rate law expression.

Explanation

To determine the rate law expression for the given decomposition reaction of hydrogen peroxide, we need to analyze the two steps of the reaction and identify the rate-determining step.

### Step-by-Step Solution:

1. **Identify the Reaction Steps**:
- Step 1: \( H_2O_2 + I^- \rightarrow H_2O + IO^- \) (slow)
- Step 2: \( H_2O_2 + IO^- \rightarrow H_2O + I^- + O_2 \) (fast)

...