Question

In the reaction:
$N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)\Delta H=-936kJ$
The yield of ammonia doesnot increase when:

• A. pressure is increased
• B. temperature is lowered
• C. pressure is lowered
• D. volume of the reaction vessel is decreased

Answer 1

Answer: (C)

pressure is lowered

In the reaction $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)\Delta H=-936kJ$. The yield of ammonia will not increase when pressure is lowered because the lowering of pressure will result in an increase in volume which shifts the equilibrium in the direction of increased volume i.e. backward.