In each of the following questions, a statement of Assertion is given followed by a corresponding statement of Reason just below it. Of the statements, mark the correct answer as
Assertion . If standard free energy change of a reaction is zero , this implies that equilibrium constant of the reaction is unity .
Reason . For a reaction in equilibrium , equilibrium constant is always unity .

Options

A. If both assertion and reason are true, and reason is the true explanation of the assertion .
B. If both assertion and reason are true but reason is the true explanation of the assertion .
C. If assertion is true, but reason is false.
D. If both assertion and reason are false .

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Analyze the Assertion
The assertion states: "If the standard free energy change of a reaction is zero, this implies that the equilibrium constant of the reaction is unity."

- The relationship between standard free energy change (ΔG°) and the equilibrium constant (Kc) is given by the equation:
\[ \Delta G° = -RT \ln K_c \]
where R is the universal gas constant and T is the temperature in Kelvin.

- If ΔG° = 0, substituting this into the equation gives:
\[ 0 = -RT \ln K_c \]
This implies that:
\[ \ln K_c = 0 \]
Therefore, exponentiating both sides results in:
\[ K_c = e^0 = 1 \]
- Thus, the assertion is correct.

### Step 2: Analyze the Reason
The reason states: "For a reaction in equilibrium, the equilibrium constant is always unity."

- This statement is not accurate. The equilibrium constant (Kc) can take various values depending on the concentrations of reactants and products at equilibrium. It is not always equal to one.
- The equilibrium constant is defined as the ratio of the concentrations of products to reactants at equilibrium, and it varies based on the specific reaction and conditions (temperature, pressure, etc.).

### Conclusion
- The assertion is true, while the reason is false.

### Final Answer
The correct answer is: Assertion is true, but Reason is false.

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