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For a particular reversible reaction at temperature T, `DeltaHandDeltaS` were found to be both +ve. If `T_(e)` is the temperature at equilibrium, the reaction would be spontaneous when

A

`T=T_(e)`

B

`T_(e)gtT`

C

`TgtT_(e)`

D

`T_(e)` is 5 times T

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The correct Answer is:
To determine when the reaction is spontaneous, we need to analyze the Gibbs free energy change (ΔG) for the reaction. The spontaneity of a reaction is indicated by the sign of ΔG, where a negative ΔG implies that the reaction is spontaneous. ### Step-by-Step Solution: 1. **Understand the Given Information**: - We are given that both ΔH (enthalpy change) and ΔS (entropy change) are positive for the reaction. - We need to find the conditions under which the reaction is spontaneous at a temperature T. 2. **Recall the Gibbs Free Energy Equation**: - The Gibbs free energy change is given by the equation: \[ \Delta G = \Delta H - T \Delta S \] 3. **Substitute the Given Values**: - Since both ΔH and ΔS are positive, we can express this in the equation: \[ \Delta G = \text{(positive)} - T \times \text{(positive)} \] 4. **Determine the Condition for Spontaneity**: - For the reaction to be spontaneous, we need ΔG to be less than 0: \[ \Delta H - T \Delta S < 0 \] - Rearranging this inequality gives: \[ \Delta H < T \Delta S \] - This implies: \[ T > \frac{\Delta H}{\Delta S} \] 5. **Identify the Equilibrium Temperature**: - The temperature at equilibrium (Te) can be defined as: \[ T_e = \frac{\Delta H}{\Delta S} \] - Therefore, for the reaction to be spontaneous, the temperature T must be greater than the equilibrium temperature Te: \[ T > T_e \] 6. **Conclusion**: - The reaction will be spontaneous when the temperature T is greater than the equilibrium temperature Te. ### Final Answer: The reaction would be spontaneous when \( T > T_e \).
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