In the manufacture of `NH_3` by Haber's process involving the reaction `N_2(g) +3H_(2)(g) overset([F_(o_2)O_2]) hArr 2NH_3(g)`
`DeltaH =-22.08` kcal . The fovourable conditions are

Options

A. High pressure and low temperature
B. Low pressure and low temperature
C. High pressure and high temperature
D. Low pressure and high temperature

Answer

To determine the favorable conditions for the manufacture of ammonia (NH₃) by the Haber process, we need to analyze the given reaction and its thermodynamic properties.

### Step-by-Step Solution:

1. **Understand the Reaction**:
The reaction for the synthesis of ammonia is:
\[ N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g) \]
The enthalpy change (ΔH) for this reaction is -22.08 kcal, indicating that the reaction is exothermic (releases heat).

2. **Effect of Pressure**:
According to Le Chatelier's Principle, if we increase the pressure of a system at equilibrium, the equilibrium will shift towards the side with fewer moles of gas to minimize the change.
- On the left side (reactants), we have 1 mole of N₂ and 3 moles of H₂, totaling 4 moles.
- On the right side (products), we have 2 moles of NH₃.
- Since there are fewer moles of gas on the product side (2 moles), increasing the pressure will favor the formation of NH₃.

3. **Effect of Temperature**:
Since the reaction is exothermic (ΔH is negative), increasing the temperature will shift the equilibrium to favor the endothermic direction (the reverse reaction) to absorb the excess heat.
- Therefore, to favor the production of NH₃, we should operate at a lower temperature.

4. **Conclusion**:
The favorable conditions for the manufacture of ammonia by the Haber process are:
- **High Pressure**: To shift the equilibrium towards the production of ammonia (fewer moles).
- **Low Temperature**: To favor the exothermic reaction and increase the yield of ammonia.

### Final Answer:
The favorable conditions for the manufacture of NH₃ by the Haber process are high pressure and low temperature.

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