Question

Pure ammonia is placed in a vessel where its dissociation is appreciable. At equilibrium,

• A. $K_P$ does not change singnificantly with pressure.
• B. $\alpha$ changes with pressure.
• C. Concentration of $N{H}_3$ does not change.
• D. Concentration of $H_2$ is less than that of $N_2$

Answer 1

The correct option is B $\alpha$ changes with pressure.

As the pressure changes, the position of the equilibrium changes in accordance with Le chatelier's principle.
Hence the value of $\alpha$ changes at constant temperature and change in pressure. The concentration of nitrogen, hydrogen and ammonia changes with change in pressure.

For 1 mole of nitrogen , 3 moles of hydrogen are formed. Hence, the concentration of nitrogen is less than the concentration of hydrogen.