Question

The equilibrium $N_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2NO\left(g\right)$ established in a reaction vessel of $2.5$ L capacity. The amounts of $N_2$ and $O_2$ taken at the start were respectively $2$ moles and $4$ moles. Half a mole of nitrogen has been used up at equilibrium. The molar concentration of nitric oxide is :

• A. $0.2$
• B. $0.8$
• C. $0.6$
• D. $0.1$

Answer 1

The correct option is C $0.6$

$N_2+O_2\rightleftharpoons 2NO$

At t = 0 2 4 0

At eq. 2-x 4-x 2x

Half a mole of nitrogen is used up at equilibrium,

$x=0.5$

So, moles of $NO=1$.

Molar conc. of $NO$ at equilibrium $=\frac{1}{2.5}=0.4$.