A catalyst remains unchanged chemically at the end of the reaction. True/False

Answer

**Step-by-Step Solution:**

1. **Definition of a Catalyst**: A catalyst is defined as a substance that increases the rate of a chemical reaction without undergoing any permanent chemical change itself.

2. **Role of a Catalyst**: Catalysts work by providing an alternative pathway for the reaction that has a lower activation energy compared to the uncatalyzed reaction. This means that they facilitate the reaction without being consumed in the process.

3. **Chemical Change**: During the reaction, a catalyst may participate in the reaction mechanism, but it is regenerated by the end of the reaction. This means that while it may form temporary intermediates, it does not change chemically in the final products.

4. **Types of Catalysts**:
- **Positive Catalysts**: These decrease the activation energy and increase the reaction rate.
- **Negative Catalysts**: These increase the activation energy and decrease the reaction rate.

5. **Conclusion**: Since a catalyst is not permanently altered by the reaction and is regenerated at the end, we can conclude that the statement "A catalyst remains unchanged chemically at the end of the reaction" is **True**.

**Final Answer**: True

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