The catalyst in the decomposition of hydrogen peroxide is _______.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Reaction**: The decomposition of hydrogen peroxide (H₂O₂) is a chemical reaction where hydrogen peroxide breaks down into water (H₂O) and oxygen gas (O₂).

2. **Identifying the Catalyst**: A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. In the case of hydrogen peroxide decomposition, a specific catalyst is used.

3. **Recognizing the Catalyst Used**: The catalyst commonly used for the decomposition of hydrogen peroxide is manganese dioxide (MnO₂).

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