Substances which alter the velocity of a reaction by mere presence, without undergoing any change in mass and compossition are termed catalyst and the phenomenon is known as catalysis
Which is incorrect for a catalyst?

Options

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

Explanation

To determine which statement is incorrect regarding catalysts, we will evaluate each provided statement one by one.

### Step-by-Step Solution:

1. **Understanding the Role of a Catalyst**:
- A catalyst is defined as a substance that alters the rate of a chemical reaction without undergoing any permanent change in its mass or composition.

2. **Evaluating Each Statement**:
- **Statement A**: "A catalyst can initiate a reaction."
- This statement is **incorrect**. A catalyst cannot initiate a reaction; it can only speed up or slow down a reaction that is already occurring by lowering the activation energy.

- **Statement B**: "A catalyst remains unchanged in quality and composition at the end of a reaction."
- This statement is **correct**. By definition, a catalyst does not change in mass or composition after the reaction.

- **Statement C**: "A catalyst does not alter the position of equilibrium in a reversible reaction."
- This statement is **correct**. A catalyst speeds up the rate at which equilibrium is reached but does not change the position of equilibrium itself.

- **Statement D**: "Catalysts are sometimes very specific in reaction."
- This statement is **correct**. Many catalysts are specific to particular reactions and cannot be used interchangeably.

3. **Conclusion**:
- The only incorrect statement regarding catalysts is **Statement A**: "A catalyst can initiate a reaction."

### Final Answer:
The incorrect statement for a catalyst is **Statement A**: "A catalyst can initiate a reaction."

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