For the reaction `N_(2)(g) + 3H_(2)(g) rarr 2NH_(3)(g) , DeltaH = -93.6 KJ mol^(-1)` the formation of `NH_(3)` is expected to increase at :

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

Explanation

To determine the conditions under which the formation of ammonia (NH₃) is expected to increase for the reaction:

\[ N_{2}(g) + 3H_{2}(g) \rightleftharpoons 2NH_{3}(g) \]

with a given enthalpy change (\( \Delta H = -93.6 \, \text{kJ mol}^{-1} \)), we can follow these steps:

### Step 1: Identify the Nature of the Reaction
The negative value of \( \Delta H \) indicates that the reaction is exothermic. This means that heat is released when ammonia is formed.

**Hint:** Remember that exothermic reactions release heat, which influences how temperature changes affect the reaction.

### Step 2: Apply Le Chatelier's Principle
According to Le Chatelier's Principle, if a system at equilibrium is subjected to a change in temperature, pressure, or concentration, the system will adjust to counteract that change and restore equilibrium.

**Hint:** Le Chatelier's Principle helps us predict how changes in conditions will affect the position of equilibrium.

### Step 3: Analyze the Effect of Temperature
For exothermic reactions, lowering the temperature favors the formation of products. Thus, to maximize the formation of ammonia, a low temperature is favorable.

**Hint:** In exothermic reactions, lower temperatures shift the equilibrium towards the products.

### Step 4: Analyze the Effect of Pressure
Next, we consider the effect of pressure. The reaction involves:

- 1 mole of nitrogen (N₂) and 3 moles of hydrogen (H₂) on the reactant side, totaling 4 moles.
- 2 moles of ammonia (NH₃) on the product side.

Increasing the pressure will shift the equilibrium towards the side with fewer moles of gas. In this case, that is the product side (2 moles of NH₃).

**Hint:** Increasing pressure favors the side of the reaction with fewer gas moles.

### Step 5: Combine the Findings
From the analysis:
- Low temperature is favorable for the formation of ammonia.
- High pressure is also favorable for the formation of ammonia.

Thus, the conditions that would increase the formation of ammonia are high pressure and low temperature.

**Final Answer:** The formation of NH₃ is expected to increase at high pressure and low temperature.