Question

${\text{N}}_2+3{\text{H}}_2\rightleftharpoons 2{\text{NH}}_3$

Which is correct statement if ${\text{N}}_2$ is added at equilibrium condition?

• A. The equilibrium will shift to forward direction because according to $2^{nd}$ law of thermodynamics, the entropy must increase in the direction of the spontaneous reaction.
• B. The condition for equilibrium is ${\text{G}}_{N_2}+3{\text{G}}_{H_2}=2{\text{G}}_{{\text{NH}}_3}$ where G is Gibbs free energy per mole of the gaseous species measured at that partial pressure. The condition of equilibrium is unaffected by the use of the catalyst, which increases the rate of both the forward and backward reactions to the same extent.
• C. The catalyst will increase the rate of forward reaction by $\alpha$ and that of backward by $\beta$.
• D. Catalyst will not alter the rate of either of the reaction.

Answer 1

The correct option is B

The condition for equilibrium is ${\text{G}}_{N_2}+3{\text{G}}_{H_2}=2{\text{G}}_{{\text{NH}}_3}$ where G is Gibbs free energy per mole of the gaseous species measured at that partial pressure. The condition of equilibrium is unaffected by the use of the catalyst, which increases the rate of both the forward and backward reactions to the same extent.

Planck's statement: Every process occurring in nature proceeds in the sense in which the sum of the entropies of all bodies taking part in the process is increased. In the limit, i.e. for reversible processes, the sum of the entropies remains unchanged.

The condition for equilibrium is ${\text{G}}_{N_2}+3{\text{G}}_{H_2}=2{\text{G}}_{{\text{NH}}_3}$ where G is Gibbs free energy per mole of the gaseous species measured at that partial pressure. The condition of equilibrium is unaffected by the use of the catalyst, which increases the rate of both the forward and backward reactions to the same extent.