The role of a catalyst is to change

Options

A. Gibbs energy of reaction
B. enthalpy of reaction
C. activation energy of reaction
D. equilibrium constant.

Answer

To solve the question regarding the role of a catalyst, we can follow these steps:

### 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 being consumed in the process.

2. **Mechanism of Action**:
- Catalysts work by providing an alternative reaction pathway. This pathway has a lower activation energy compared to the uncatalyzed reaction.

3. **Effect on Activation Energy**:
- By lowering the activation energy, catalysts make it easier for reactants to convert into products, thus increasing the rate of the reaction.

4. **Conclusion**:
- Therefore, the primary role of a catalyst is to change the activation energy of a reaction, making it lower, which in turn increases the reaction rate.

5. **Correct Option**:
- Based on the explanation, the correct answer to the question is option C: "the role of catalyst is to change activation energy of reaction."