---
title: "The decomposition of hydrogen peroxide, \\(\\text{H}_2\\text{O}_2\\text{(aq)}\\), is catalyzed by iodide ions, \\(\\text{I}^-\\text{(aq)}\\), according to the overall reaction:  \\[ 2\\text{ H}_2\\text{O}_2\\text{(aq)} \\rightarrow 2\\text{ H}_2\\text{O}\\text{(l)} + \\text{O}_2\\text{(g)} \\]  Kinetic measurements demonstrate that the reaction is first order with respect to \\(\\text{H}_2\\text{O}_2\\) and first order with respect to \\(\\text{I}^-\\), giving the experimental rate law:  \\[ \\text{Rate} = k [\\text{H}_2\\text{O}_2][\\text{I}^-] \\]  Which of the following proposed mechanisms is consistent with both the overall balanced equation and the experimental rate law?"
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url: "https://nerd-notes.com/ubq/123639/"
date_modified: "2026-09-28T12:01:52+00:00"
---

# The decomposition of hydrogen peroxide, \(\text{H}_2\text{O}_2\text{(aq)}\), is catalyzed by iodide ions, \(\text{I}^-\text{(aq)}\), according to the overall reaction:

\[ 2\text{ H}_2\text{O}_2\text{(aq)} \rightarrow 2\text{ H}_2\text{O}\text{(l)} + \text{O}_2\text{(g)} \]

Kinetic measurements demonstrate that the reaction is first order with respect to \(\text{H}_2\text{O}_2\) and first order with respect to \(\text{I}^-\), giving the experimental rate law:

\[ \text{Rate} = k [\text{H}_2\text{O}_2][\text{I}^-] \]

Which of the following proposed mechanisms is consistent with both the overall balanced equation and the experimental rate law?

The decomposition of hydrogen peroxide, \(\text{H}_2\text{O}_2\text{(aq)}\), is catalyzed by iodide ions, \(\text{I}^-\text{(aq)}\), according to the overall reaction:

\[ 2\text{ H}_2\text{O}_2\text{(aq)} \rightarrow 2\text{ H}_2\text{O}\text{(l)} + \text{O}_2\text{(g)} \]

Kinetic measurements demonstrate that the reaction is first order with respect to \(\text{H}_2\text{O}_2\) and first order with respect to \(\text{I}^-\), giving the experimental rate law:

\[ \text{Rate} = k [\text{H}_2\text{O}_2][\text{I}^-] \]

Which of the following proposed mechanisms is consistent with both the overall balanced equation and the experimental rate law?

- **A.** Step 1 (fast, equilibrium): \(\text{H}_2\text{O}_2\text{(aq)} + \text{I}^-\text{(aq)} \rightleftharpoons \text{IO}^-\text{(aq)} + \text{H}_2\text{O}\text{(l)}\) Step 2 (slow): \(\text{H}_2\text{O}_2\text{(aq)} + \text{IO}^-\text{(aq)} \rightarrow \text{H}_2\text{O}\text{(l)} + \text{O}_2\text{(g)} + \text{I}^-\text{(aq)}\)
- **B.** Step 1 (slow): \(\text{H}_2\text{O}_2\text{(aq)} + \text{I}^-\text{(aq)} \rightarrow \text{H}_2\text{O}\text{(l)} + \text{IO}^-\text{(aq)}\) Step 2 (fast): \(\text{H}_2\text{O}_2\text{(aq)} + \text{IO}^-\text{(aq)} \rightarrow \text{H}_2\text{O}\text{(l)} + \text{O}_2\text{(g)} + \text{I}^-\text{(aq)}\)
- **C.** Step 1 (slow): \(2\text{ H}_2\text{O}_2\text{(aq)} + \text{I}^-\text{(aq)} \rightarrow 2\text{ H}_2\text{O}\text{(l)} + \text{IO}_2^-\text{(aq)}\) Step 2 (fast): \(\text{IO}_2^-\text{(aq)} \rightarrow \text{I}^-\text{(aq)} + \text{O}_2\text{(g)}\)
- **D.** Step 1 (slow): \(\text{H}_2\text{O}_2\text{(aq)} \rightarrow \text{H}_2\text{O}\text{(l)} + \text{O}\text{(g)}\) Step 2 (fast): \(\text{O}\text{(g)} + \text{H}_2\text{O}_2\text{(aq)} + \text{I}^-\text{(aq)} \rightarrow \text{H}_2\text{O}\text{(l)} + \text{O}_2\text{(g)} + \text{I}^-\text{(aq)}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123639/*