---
title: "A student adds a small amount of potassium iodide to accelerate the decomposition of residual hydrogen peroxide in a water sample. The proposed mechanism is shown below.  Step 1: \\(\\text{H}_2\\text{O}_2\\text{(aq)}+\\text{I}^-\\text{(aq)}\\rightarrow\\text{IO}^-\\text{(aq)}+\\text{H}_2\\text{O(l)}\\)  Step 2: \\(\\text{H}_2\\text{O}_2\\text{(aq)}+\\text{IO}^-\\text{(aq)}\\rightarrow\\text{I}^-\\text{(aq)}+\\text{H}_2\\text{O(l)}+\\text{O}_2\\text{(g)}\\)  Which species acts as a catalyst in the proposed mechanism?"
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url: "https://nerd-notes.com/ubq/119351/"
date_modified: "2026-08-19T12:39:56+00:00"
---

# A student adds a small amount of potassium iodide to accelerate the decomposition of residual hydrogen peroxide in a water sample. The proposed mechanism is shown below.

Step 1: \(\text{H}_2\text{O}_2\text{(aq)}+\text{I}^-\text{(aq)}\rightarrow\text{IO}^-\text{(aq)}+\text{H}_2\text{O(l)}\)

Step 2: \(\text{H}_2\text{O}_2\text{(aq)}+\text{IO}^-\text{(aq)}\rightarrow\text{I}^-\text{(aq)}+\text{H}_2\text{O(l)}+\text{O}_2\text{(g)}\)

Which species acts as a catalyst in the proposed mechanism?

A student adds a small amount of potassium iodide to accelerate the decomposition of residual hydrogen peroxide in a water sample. The proposed mechanism is shown below.

Step 1: \(\text{H}_2\text{O}_2\text{(aq)}+\text{I}^-\text{(aq)}\rightarrow\text{IO}^-\text{(aq)}+\text{H}_2\text{O(l)}\)

Step 2: \(\text{H}_2\text{O}_2\text{(aq)}+\text{IO}^-\text{(aq)}\rightarrow\text{I}^-\text{(aq)}+\text{H}_2\text{O(l)}+\text{O}_2\text{(g)}\)

Which species acts as a catalyst in the proposed mechanism?

- **A.** \(\text{H}_2\text{O}_2\text{(aq)}\)
- **B.** \(\text{I}^-\text{(aq)}\)
- **C.** \(\text{IO}^-\text{(aq)}\)
- **D.** \(\text{O}_2\text{(g)}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119351/*