For the formation of atomic hydrogen from the molecular hydrogen, the favourable condition will be:-

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

Explanation

To determine the favorable conditions for the formation of atomic hydrogen from molecular hydrogen, we can analyze the reaction and apply the principles of thermodynamics and Le Chatelier's principle. Here’s a step-by-step solution:

### Step 1: Understand the Reaction
The reaction for the formation of atomic hydrogen from molecular hydrogen can be represented as:
\[ \text{H}_2(g) \rightarrow 2\text{H}(g) \]
This means that one mole of molecular hydrogen (H₂) dissociates into two moles of atomic hydrogen (H).

### Step 2: Enthalpy of Atomization
The enthalpy of atomization refers to the energy required to dissociate one mole of a substance into its gaseous atoms. For hydrogen, this process is endothermic, meaning it requires heat:
- \(\Delta H > 0\) (positive change in enthalpy).

### Step 3: Apply Le Chatelier's Principle
According to Le Chatelier's principle, if a system at equilibrium is subjected to a change in conditions (such as temperature or pressure), the equilibrium will shift in a direction that counteracts that change.

### Step 4: Effect of Temperature
Since the reaction is endothermic, increasing the temperature will favor the formation of atomic hydrogen:
- Higher temperature is favorable for endothermic reactions.

### Step 5: Effect of Pressure
Next, we analyze the effect of pressure. In the reaction:
- Reactants: 1 mole of H₂
- Products: 2 moles of H

Since the number of moles of products (2) is greater than the number of moles of reactants (1), increasing the pressure would shift the equilibrium towards the side with fewer moles (the reactants). Therefore, to favor the formation of atomic hydrogen, we need to apply low pressure.

### Conclusion
The favorable conditions for the formation of atomic hydrogen from molecular hydrogen are:
- **High Temperature** (to favor the endothermic reaction)
- **Low Pressure** (to favor the side with more moles of gas)

### Final Answer
The favorable conditions for the formation of atomic hydrogen from molecular hydrogen are high temperature and low pressure.

---