Which is not correct for catalyst . It :-

Options

A. Reduces activation energy of reaction
B. Specific in nature
C. Enhances the rate of reaction in both directions
D. Changes enthalpy of reaction

Explanation

To determine which statement about catalysts is not correct, we will analyze each option one by one.

### Step-by-Step Solution:

1. **Understanding the Role of Catalysts**:
- Catalysts are substances that increase the rate of a chemical reaction without being consumed in the process. They work by lowering the activation energy required for the reaction to occur.

2. **Analyzing Each Option**:
- **Option 1: Reduces activation energy of reaction**:
- This statement is correct. Catalysts lower the activation energy, allowing the reaction to proceed more quickly.

- **Option 2: Specific in nature**:
- This statement is also correct. Catalysts are specific to certain reactions; a particular catalyst may work for one reaction but not for another.

- **Option 3: Enhances the rate of reaction in both directions**:
- This statement is correct as well. Catalysts can speed up both the forward and reverse reactions in a reversible reaction, thus maintaining equilibrium.

- **Option 4: Changes enthalpy of reaction**:
- This statement is incorrect. Catalysts do not change the enthalpy of the reaction. They only affect the rate of the reaction, not the overall energy change (enthalpy) of the reactants and products.

3. **Conclusion**:
- The statement that is not correct for catalysts is **Option 4: Changes enthalpy of reaction**.

### Final Answer:
**Option 4: Changes enthalpy of reaction** is not correct for catalysts.

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