Question

If in the reaction \(N_2O_4 \rightleftharpoons 2NO_2\), \( \alpha \) is the degree of dissociation of \(N_2O_4\), then total number of moles at equilibrium is:

• A. \(1 - \alpha\)
• B. \(1 + \alpha\)
• C. \(1 + 2\alpha\)
• D. \(1 + \frac{\alpha}{2}\)

Hint:

Total moles = initial + change due to dissociation.

Answer 1

The Correct Option is B

Concept: Let initial moles of \(N_2O_4 = 1\).

Step 1: Dissociation.
\[ N_2O_4 \rightarrow 2NO_2 \] Dissociated amount = \(\alpha\) \[ N_2O_4 = 1 - \alpha,\quad NO_2 = 2\alpha \]

Step 2: Total moles.
\[ n = (1 - \alpha) + 2\alpha = 1 + \alpha \]