Which of the following conditions is not favourable for the feasibility of a reaction?

Options

A. `DeltaH = +ve, T DeltaS + ve and T DeltaS gt DeltaH`
B. `DeltaH = -ve, TDeltaS = +ve`
C. `DeltaH = -ve, T DeltaS = -ve and TDeltaS lt DeltaH`
D. `DeltaH = + ve, T DeltaS = + ve and T DeltaS lt DeltaH`

Answer

To determine which of the given conditions is not favorable for the feasibility of a reaction, we need to analyze the Gibbs free energy change (ΔG) for each condition. The feasibility of a reaction is typically assessed based on whether ΔG is negative (indicating the reaction is spontaneous and feasible) or positive (indicating the reaction is non-spontaneous and not feasible).

### Step-by-Step Solution:

1. **Understand the Gibbs Free Energy Equation**:
\[ \Delta G = \Delta H - T \Delta S \]
Where:
- ΔG = Gibbs free energy change
- ΔH = Enthalpy change
- T = Temperature (in Kelvin)
- ΔS = Entropy change

2. **Analyze Each Condition**:
- **Condition A**: ΔH is positive, TΔS is positive, and TΔS > ΔH.
- Here, ΔG = ΔH - TΔS = positive - positive. Since TΔS > ΔH, ΔG will be negative (feasible).

- **Condition B**: ΔH is negative, TΔS is positive.
- Here, ΔG = ΔH - TΔS = negative - positive. This will also yield a negative ΔG (feasible).

- **Condition C**: ΔH is negative, TΔS is negative, and ΔH > TΔS.
- Here, ΔG = ΔH - TΔS = negative - negative. Since ΔH is greater in magnitude than TΔS, ΔG will be negative (feasible).

- **Condition D**: ΔH is positive, TΔS is positive, and ΔH > TΔS.
- Here, ΔG = ΔH - TΔS = positive - positive. Since ΔH is greater than TΔS, ΔG will be positive (not feasible).

3. **Conclusion**:
- The condition that results in a positive ΔG is **Condition D**. Therefore, this condition is not favorable for the feasibility of a reaction.

### Final Answer:
**Condition D** is not favorable for the feasibility of a reaction.

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