Which of the following is not correct?

The given solution explains the conditions under which a chemical reaction is spontaneous, based on the Gibbs free energy equation:

∆G = ∆H - T∆S

Explanation:

1. Sign of ∆G and Spontaneity:
   • For a reaction to be spontaneous, the Gibbs free energy change (∆G) must be negative (∆G < 0).
   • This negative value indicates that the process can occur without external energy input.
2. Relationship Between Entropy (∆S), Enthalpy (∆H), and Temperature (T):
   • Gibbs free energy depends on the balance of enthalpy (∆H), entropy (∆S), and temperature (T).
   • A spontaneous reaction is guaranteed when:
     • ∆H (enthalpy change) is negative (exothermic reaction).
     • ∆S (entropy change) is positive (disorder increases).

3. Concept Check:

   If asked, "which of the following is not correct" about spontaneity, an incorrect statement might claim that a reaction can be spontaneous with both ∆H positive and ∆S negative, which is not correct because it would lead to a positive ∆G.

Conclusion:

In summary, for spontaneity:

• Negative ∆G is required.
• ∆H negative and ∆S positive ensures spontaneity.

If a question asks "which of the following is not correct", carefully analyze whether the given conditions align with the requirements for a spontaneous reaction based on Gibbs free energy.