Question

Given the following reaction at equilibrium $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$. Some inert gas at constant pressure is added to the system. Predict which of the following facts will be affected :

• A. more $N{H}_3\left(g\right)$ is produced
• B. less $N{H}_3\left(g\right)$ is produced
• C. no affect on the equilibrium
• D. $K_P$ of the reaction is decreased

Answer 1

Answer: (B)

less $N{H}_3\left(g\right)$ is produced

When an inert gas is added to the equilibrium mixture at constant pressure, the equilibrium will shift in the direction in which there is increase in the number of moles of gas. In the reaction for the formation of ammonia, the number of moles of gaseous reactants are greater than the number of moles of gaseous products. Hence, when inert gas is added, the equilibrium will shift in the reverse direction. Hence, less ammonia is obtained.