Which of the following statements is/are correct in the case of heterogenous catalyst?

Options

A. The catalyst lowers the energy of activation.
B. The catalyst actually forms a compound with the reactant.
C. The surface of the catalyst plays a very important role.
D. There is no change in the energy of activation.

Answer

To determine which statements regarding heterogeneous catalysts are correct, we need to analyze each statement based on the properties and behavior of heterogeneous catalysts.

### Step-by-Step Solution:

1. **Understanding Heterogeneous Catalysts**:
- Heterogeneous catalysts are substances that speed up a chemical reaction while remaining in a different phase from the reactants. For example, a solid catalyst can facilitate a reaction between gaseous reactants.

2. **Evaluating the Statements**:
- **Statement 1**: "The catalyst lowers the energy of activation."
- This statement is **correct**. Catalysts provide an alternative pathway for the reaction with a lower activation energy, thus speeding up the reaction.

- **Statement 2**: "Catalyst actually forms a compound with the reactant."
- This statement can be **correct** in some cases. While not all heterogeneous catalysts form stable compounds with reactants, they can form temporary complexes during the reaction process. Thus, this statement is generally considered **correct**.

- **Statement 3**: "The surface of the catalyst plays a very important role."
- This statement is **correct**. The reaction occurs at the surface of the catalyst, and the surface area is crucial for the reaction rate. The more surface area available, the more reactant molecules can interact with the catalyst.

- **Statement 4**: "There is no change in the energy of activation."
- This statement is **incorrect**. The purpose of a catalyst is to lower the activation energy, so there is indeed a change in the energy of activation when a catalyst is used.

3. **Conclusion**:
- The correct statements regarding heterogeneous catalysts are:
- Statement 1: Correct
- Statement 2: Correct
- Statement 3: Correct
- Statement 4: Incorrect

### Final Answer:
The correct statements are: 1, 2, and 3.

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