What are the favourable conditions for the synthesis of ammonia.

Options

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

Answer

To determine the favorable conditions for the synthesis of ammonia (NH₃), we need to analyze the reaction and apply the principles of chemical equilibrium.

### Step-by-Step Solution:

1. **Write the Balanced Chemical Equation**:
The synthesis of ammonia can be represented by the following balanced equation:
\[ N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g) + \text{heat} \]
This indicates that nitrogen gas reacts with hydrogen gas to produce ammonia and releases heat.

2. **Identify the Nature of the Reaction**:
The reaction is exothermic, as indicated by the release of heat. In exothermic reactions, the production of heat favors the formation of products at lower temperatures.

3. **Determine the Effect of Temperature**:
Since the reaction is exothermic, lower temperatures will favor the forward reaction (formation of ammonia). Thus, we conclude:
- **Favorable Condition**: Low Temperature

4. **Calculate Change in Moles (Δn)**:
To understand the effect of pressure, we need to calculate the change in the number of moles of gases during the reaction:
\[ \Delta n = n_{\text{products}} - n_{\text{reactants}} = 2 - (1 + 3) = 2 - 4 = -2 \]
This indicates that there is a decrease in the number of moles of gas as the reaction proceeds from reactants to products.

5. **Determine the Effect of Pressure**:
According to Le Chatelier's principle, increasing the pressure will favor the side of the reaction with fewer moles of gas. Since we have a decrease in moles (from 4 moles of reactants to 2 moles of products), we conclude:
- **Favorable Condition**: High Pressure

6. **Summarize the Favourable Conditions**:
Based on the analysis, the favorable conditions for the synthesis of ammonia are:
- Low Temperature
- High Pressure

### Final Answer:
The favorable conditions for the synthesis of ammonia are **low temperature and high pressure**.

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