For the given reaction 2A(g)+ B(g) `hArr ` C(g) , `Delta`H = x kJ which of the following favour the reactants ?

Options

A. Low pressure
B. High pressure
C. Low temperature
D. Catalyst

Answer

To determine which conditions favor the reactants for the reaction \( 2A(g) + B(g) \rightleftharpoons C(g) \) with \( \Delta H = x \, \text{kJ} \) (indicating that the forward reaction is endothermic), we can analyze the situation using Le Chatelier's principle. Here’s a step-by-step solution:

### Step 1: Understand the Reaction
The reaction involves:
- Reactants: \( 2A + B \) (3 moles of gas)
- Product: \( C \) (1 mole of gas)

### Step 2: Identify the Nature of the Reaction
Since \( \Delta H = x \, \text{kJ} \) is positive, the forward reaction (formation of \( C \)) is endothermic. This means that heat is absorbed when the reaction proceeds from reactants to products.

### Step 3: Apply Le Chatelier's Principle
Le Chatelier's principle states that if a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will adjust to counteract that change.

### Step 4: Analyze Pressure Effects
- The reaction has 3 moles of gas on the reactant side and 1 mole of gas on the product side.
- According to Le Chatelier's principle, decreasing the pressure will favor the side with more moles of gas (the reactants in this case).
- Therefore, **low pressure favors the reactants**.

### Step 5: Analyze Temperature Effects
- Since the forward reaction is endothermic, lowering the temperature will favor the exothermic reverse reaction (formation of reactants).
- Therefore, **low temperature also favors the reactants**.

### Step 6: Consider the Role of a Catalyst
- A catalyst speeds up both the forward and reverse reactions equally but does not affect the position of equilibrium.
- Therefore, a catalyst does not favor either the reactants or products.

### Conclusion
Based on the analysis:
- **Low pressure** and **low temperature** favor the reactants.

### Final Answer
The conditions that favor the reactants are:
1. Low Pressure
2. Low Temperature