Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): For a reversible reaction, if the standard enthalpy change equals the product of temperature and standard entropy change ( H^ = T S^ ), then the equilibrium constant K is 1 . Reason (R): For any reversible reaction at equilibrium, the standard Gibbs free energy change ( G^ ) is always zero. In the

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Assertion (A) is correct: The standard Gibbs free energy change is given by G^ = H^ - T S^ . If H^ = T S^ , then G^ = 0 . Using the relation G^ = -RT K , we get -RT K = 0 , which implies K = 0 and therefore K = 1 . Reason (R) is incorrect: At equilibrium, it is the actual Gibbs free energy change ( G ) that is always zero, not the standard Gibbs free energy change ( G^ ). G^ is zero only when the equilibrium constant K = 1 . Answer: Assertion is correct but Reason is not correct