Question

One mole of $N_2$ and 3 moles of $H_2$ are mixed in a litle flask. If $50\%N_2$ is converted into ammonia by the reaction, $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$
then the total number of moles of gas at equilibrium is

• A. 1.5
• B. 3
• C. 4.5
• D. 6

Answer 1

The correct option is B 3

$\text{Degree of dissociatio}\left(\alpha \right)=50\%=\frac{50}{100}=0.5$
$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$
Initial mole 1 3 0
At eqb. $1-\alpha$ $3-3\alpha$ $2\alpha$
$\text{Total moles at equilibrium},n_T=1-\alpha +3-3\alpha +2\alpha$
$n_T=4-2\alpha$
$n_T=4-2\times 0.5=3$