Question

For the dissociation reaction, \( \text{H}_2 \rightarrow \text{H} + \text{H} \), \( \Delta H = 162 \, \text{Kcal} \), heat of atomisation of H is

• A. 81 Kcal
• B. 162 Kcal
• C. 162 Kcal
• D. 218 Kcal

Hint:

The heat of atomisation is half the heat of dissociation for diatomic molecules like \( \text{H}_2 \).

Answer 1

The Correct Option is A

Step 1: Apply the concept of enthalpy change.
In the dissociation of \( \text{H}_2 \), the heat of atomisation is half of the given value of \( \Delta H \).
Step 2: Conclusion.
The heat of atomisation of H is \( 81 \, \text{Kcal} \). Final Answer: \[ \boxed{81 \, \text{Kcal}} \]