Question

Consider the following reaction:
$N_2{O}_{4\left(g\right)}+Heat\rightleftharpoons 2{NO}_{2\left(g\right)}$
How is the composition of equilibrium mixture affected by:
(i) A change in temperature
(ii) A change in pressure
(iii) A change in concentration of $N_2{O}_4$
(iv) The removal of ${NO}_2$ from the reaction mixture.

Answer 1

(i) With increase in temperature, the equilibrium will shift to right according to Le Chatelier's principle. Thus, with an increase in temperature, more ${NO}_2\left(g\right)$ is produced and vice-versa.
(ii) Forward reaction is accompanied by increase in mole number. According to Le Chateliers principle with increase in pressure the equilibrium will shift in that direction where number of mole decreases. i.e., $N_2{O}_4\left(g\right)$ direction.
(iii) If we increase concentration of $N_2{O}_4$, then to keep equilibrium constant, more $N_2{O}_4$ decomposes and greater amount of ${NO}_2$ is produced.
(iv) If we remove ${NO}_2$ from the reaction mixture then to keep equilibrium constant more $N_2{O}_4$ decomposes to produce ${NO}_2$ to minimize that effect.