Q.
The decomposition of $N_{2}O_{4}$ to $NO_{2}$ is carried out at 280 K in chloroform. When equilibrium has been established, 0.2 mole of $N_{2}O_{4}$ and $2 \times 10^{- 3}$ mole of$NO_{2}$ are present in 2 L solution. The equilibrium constant for reaction $N_{2}O_{4} \rightleftharpoons 2{NO}_{2}$ is