Question

Assertion: For every chemical reaction at equilibrium, the standard Gibbs energy of reaction is zero.
Reason: At constant temperature and pressure, chemical reactions are spontaneous in the direction of decreasing Gibbs energy.

• A. The Assertion is True, Reason is True; Reason is the correct explanation for Assertion
• B. The Assertion is True, Reason is True; Reason is NOT a correct explanation for Assertion
• C. The Assertion is True, Reason is False
• D. The Assertion is False, Reason is True

Answer 1

The correct option is D The Assertion is False, Reason is True

The standard Gibb's energy for a reaction is given by $\Delta G^o$.

At equilibrium, $\Delta G=0$ whereas $\Delta G^o$ for a reaction may or may not be zero.
For a spontaneous process, Gibb's energy for a reaction is always negative, $\Delta G<0$

Hence, Assertion is false but Reason is true.