Question

Which of the following is not correct?

• A. ΔG is negative for a spontaneous reaction
• B. ΔG is zero for a reversible reaction
• C. ΔG is positive for a spontaneous reaction
• D. ΔG is positive for a non-spontaneous reaction

Answer 1

Answer: (C)

ΔG is positive for a spontaneous reaction

Answer 2

For a process to be spontaneous, the Gibbs free energy change (ΔG) must be negative at constant temperature and pressure, indicating that the reaction proceeds forward without external energy input. Conversely, for a non-spontaneous process, ΔG is positive, meaning the reaction does not proceed unless energy is supplied. For a reaction in equilibrium (reversible), ΔG = 0.
Thus, statement (3) is incorrect as it suggests ΔG is positive for a spontaneous reaction, which contradicts the condition for spontaneity.

(ΔG)P,T = (+) for non-spontaneous process
So, the correct answer is : Option 3.