Which of the following statements is false?

Options

A. A catalyst is highly specific.
B. The percentage of yield of products can be influenced by a catalyst.
C. All catalysts have a large surface area.
D. Composition of a catalyst changes during the reaction.

Explanation

To determine which of the statements is false, we will analyze each option provided regarding catalysts and their properties.

### Step-by-Step Solution:

1. **Understand the Definition of a Catalyst**:
- A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.

2. **Evaluate Option 1**:
- **Statement**: "Catalyst is highly specific."
- **Analysis**: This statement is true. Catalysts often have specific reactions they catalyze, meaning they are designed to work with particular reactants.

3. **Evaluate Option 2**:
- **Statement**: "The percentage of yield of product can be influenced by catalyst."
- **Analysis**: This statement is false. While catalysts speed up reactions, they do not affect the overall yield of the products. The yield is determined by the reaction conditions and the reactants used, not by the catalyst.

4. **Evaluate Option 3**:
- **Statement**: "All catalysts have larger surface area."
- **Analysis**: This statement is generally true. Many catalysts, especially heterogeneous catalysts, are designed to have a large surface area to facilitate more effective interactions with reactants.

5. **Evaluate Option 4**:
- **Statement**: "Composition of catalyst changes during the reaction."
- **Analysis**: This statement is false. The composition of a catalyst remains unchanged after the reaction, meaning it can be used repeatedly.

6. **Conclusion**:
- The false statements are Option 2 and Option 4. However, since the question asks for one false statement, we can conclude that Option 2 is a clear false statement regarding the influence of catalysts on product yield.

### Final Answer:
The false statement is: **"The percentage of yield of product can be influenced by catalyst." (Option 2)**