Which is false for catalyst ?

Options

A. A catalyst can initiate a reaction
B. It does not alter the position of equilibrium in a reversible reaction
C. A catalyst remains unchanged in quality and composition at the end of reaction
D. Catalysts are sometimes very specific in respect of a reaction

Answer

To determine which statement about catalysts is false, let's analyze the properties and functions of catalysts step by step.

### Step 1: Define a Catalyst
A catalyst is a substance that alters the rate of a chemical reaction without being consumed in the process. It can either increase (positive catalyst) or decrease (negative catalyst) the reaction rate.

**Hint:** Remember that catalysts are not consumed in the reaction; they remain unchanged.

### Step 2: Assess the Statements
1. **Statement 1:** A catalyst can never initiate a reaction.
- This statement is true. Catalysts do not start reactions; they only speed them up or slow them down if the reaction is already occurring.

2. **Statement 2:** A catalyst does not alter the position of equilibrium in a reversible reaction.
- This statement is also true. Catalysts do not affect the equilibrium position; they only help the system reach equilibrium faster.

3. **Statement 3:** A catalyst remains unchanged in quality and composition at the end of the reaction.
- This statement is true as well. Catalysts retain their original form and properties after the reaction.

4. **Statement 4:** Catalysts are sometimes very specific in respect of a reaction.
- This statement is true. Some catalysts are specific to certain reactions, meaning they can enhance the rate of one reaction while inhibiting another.

### Step 3: Identify the False Statement
After analyzing all the statements, we find that:
- The first statement, "A catalyst can never initiate a reaction," is indeed true.
- All other statements are also true.

Thus, the false statement is:
- **A catalyst can never initiate a reaction.**

### Final Answer
The false statement regarding catalysts is: **A catalyst can never initiate a reaction.**