Which of the following statement is not correct?

Options

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

Answer

To determine which statement is not correct regarding equilibrium and catalysts, let's analyze each option step by step.

### Step 1: Analyze the first statement
**Statement:** The value of the equilibrium constant is changed in the presence of a catalyst in the reaction at equilibrium.

**Analysis:** This statement is incorrect. A catalyst does not change the value of the equilibrium constant. It only speeds up the rate at which equilibrium is reached by lowering the activation energy of the reaction. The equilibrium constant remains constant at a given temperature and is not affected by the presence of a catalyst.

### Step 2: Analyze the second statement
**Statement:** Enzymes mainly catalyze biochemical reactions.

**Analysis:** This statement is correct. Enzymes are biological catalysts that facilitate biochemical reactions in living organisms. They play a crucial role in various metabolic processes.

### Step 3: Analyze the third statement
**Statement:** Co-enzymes increase the catalytic activity of enzymes.

**Analysis:** This statement is also correct. Co-enzymes are non-protein molecules that assist enzymes in catalyzing reactions, enhancing their activity and efficiency.

### Step 4: Analyze the fourth statement
**Statement:** A catalyst does not initiate any reaction.

**Analysis:** This statement is correct. A catalyst increases the rate of a reaction but does not initiate it. If the reactants do not have the necessary energy to react, adding a catalyst will not cause them to react.

### Conclusion
After analyzing all the statements, the first statement is the only one that is not correct. The presence of a catalyst does not change the equilibrium constant; it only helps in reaching equilibrium faster.

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

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