Under what conditions of tenperature and pressure the formation of atomic hydrogen from molecular hydrogen will be favoured.

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 conditions of temperature and pressure under which the formation of atomic hydrogen from molecular hydrogen is favored, we need to analyze the reaction and its characteristics.

### Step-by-Step Solution:

1. **Identify the Reaction**: The decomposition of molecular hydrogen (H₂) into atomic hydrogen (2H) can be represented as:
\[ H_2(g) \rightleftharpoons 2H(g) \]

2. **Determine the Nature of the Reaction**: This reaction is endothermic, meaning it absorbs heat. The breaking of the H-H bond requires energy input.

3. **Effect of Temperature**: For endothermic reactions, increasing the temperature shifts the equilibrium position to the right (toward the products). Therefore, to favor the formation of atomic hydrogen, we need to apply **high temperature**.

4. **Effect of Pressure**: According to Le Chatelier's principle, if the number of moles of gas increases on the product side compared to the reactant side, lowering the pressure will favor the formation of products. In this reaction, 1 mole of H₂ decomposes into 2 moles of H. Thus, to favor the formation of atomic hydrogen, we need to apply **low pressure**.

5. **Conclusion**: The conditions that favor the formation of atomic hydrogen from molecular hydrogen are **high temperature and low pressure**.

### Final Answer:
The formation of atomic hydrogen from molecular hydrogen is favored under conditions of **high temperature and low pressure**.

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