Thermodynamics

Which of the following is not correct?

1. G is positive for a spontaneous reaction
2. G is positive for a non-spontaneous reaction
3. G is zero for a reversible reaction
4. G is negative for a spontaneous reaction

Answer

(1) G is positive for a spontaneous reaction

Solution

At constant T and P:

G < 0: spontaneous

G > 0: non-spontaneous

G = 0: equilibrium (reversible process)

(A): G positive for a spontaneous reaction ⇒ (A) is not correct

(B), (C), (D): agree with these criteria ⇒ (B), (C), (D) are correct

Answer: (1)