For an endothermic reaction, `DeltaS` is positive. Then the reaction is

Options

A. Feasible when `TDeltaSgtDeltaH`
B. Feasible when `DeltaHgtTDeltaS`
C. Feasible at all temperatures
D. Not feasible at all

Answer

To solve the question regarding the feasibility of an endothermic reaction with a positive change in entropy (ΔS), we can follow these steps:

### Step 1: Understand the terms
- **Endothermic reaction**: A reaction that absorbs heat, resulting in a positive change in enthalpy (ΔH > 0).
- **Change in entropy (ΔS)**: A measure of disorder or randomness in a system. A positive ΔS indicates an increase in disorder.

### Step 2: Use the Gibbs Free Energy Equation
The Gibbs Free Energy (ΔG) is given by the equation:
\[ \Delta G = \Delta H - T \Delta S \]
Where:
- ΔG = change in Gibbs free energy
- ΔH = change in enthalpy
- T = absolute temperature (in Kelvin)
- ΔS = change in entropy

### Step 3: Determine the conditions for spontaneity
A reaction is spontaneous (feasible) when:
\[ \Delta G < 0 \]
This means:
\[ \Delta H - T \Delta S < 0 \]
Rearranging gives:
\[ \Delta H < T \Delta S \]

### Step 4: Analyze the implications
Since we know that:
- ΔH is positive (because it is an endothermic reaction).
- ΔS is also positive (as given in the question).

For the reaction to be feasible, the condition ΔH < TΔS must hold true. Since both ΔH and T are positive, this implies that at sufficiently high temperatures (T), the term TΔS can exceed ΔH, making ΔG negative.

### Step 5: Conclusion
Thus, the reaction is feasible when:
\[ T \Delta S > \Delta H \]
This indicates that the reaction is feasible at higher temperatures where the increase in entropy can compensate for the positive enthalpy change.

### Final Answer
The reaction is feasible when \( T \Delta S > \Delta H \).

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