Which one of the following statements is not correct ?

Options

A. Catalyst does not initiate any reaction
B. The value of equilibrium constant is changed in the presence of a catalyst in the reaction at equilibrium
C. Enzymes catalyse mainly bio - chemical reactions
D. Coenzymes increase the catalytic activity of enzyme

Answer

To determine which statement is not correct regarding catalysts and their role in chemical reactions, we will analyze each of the provided statements one by one.

### Step 1: Analyze the first statement
**Statement 1:** "The catalyst does not initiate any reaction."
- A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. However, it does not initiate a reaction; it only speeds up the reaction that can occur spontaneously. Therefore, this statement is correct.

### Step 2: Analyze the second statement
**Statement 2:** "The value of equilibrium constant is changed in the presence of catalyst in the reaction at equilibrium."
- The equilibrium constant (K) of a reaction is determined by the ratio of the concentrations of products to reactants at equilibrium. A catalyst does not change the position of equilibrium or the value of the equilibrium constant; it only helps the system reach equilibrium faster. Therefore, this statement is incorrect.

### Step 3: Analyze the third statement
**Statement 3:** "Enzyme catalysts are mainly biochemical reactions."
- Enzymes are biological catalysts that facilitate biochemical reactions in living organisms. This statement is correct as enzymes play a crucial role in processes such as digestion and metabolism.

### Conclusion
Based on the analysis above, the statement that is not correct is **Statement 2:** "The value of equilibrium constant is changed in the presence of catalyst in the reaction at equilibrium."

### Final Answer
The statement that is not correct is: **"The value of equilibrium constant is changed in the presence of catalyst in the reaction at equilibrium."**

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