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For a given reversible reaction at temperature T, both ΔH and ΔS are positive. If Tₑ denotes the equilibrium temperature, under what condition will the reaction be spontaneous?

1. Tₑ is greater than T
2. T is greater than Tₑ
3. Tₑ is five times T
4. T is equal to Tₑ

Correct answer: T is greater than Tₑ

Solution

A reaction is spontaneous when the Gibbs free energy change (ΔG) is negative. Since both ΔH and ΔS are positive, the reaction will be spontaneous at temperatures higher than the equilibrium temperature (Tₑ), where the entropy increase can outweigh the enthalpy increase, leading to a negative ΔG.

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