Question

In which one of the following equilibria, the increase of pressure over the equilibrium will favour the reaction?

• A. Pecomposition equilibrium of HI
• B. Formation equilibrium of $SO_3$
• C. Decomposition equilibrium of $NH_3$
• D. Formation equilibrium of $PCl_{5}$

Answer 1

Answer: (C)

Decomposition equilibrium of $NH_3$

Answer 2

In the decomposition reaction of $NH _{3}$, the number of moles of products formed is greater than that of reactant involved.
$2 NH _{3} \rightleftharpoons N _{2}+3 H _{2}$
Increase in pressure favours the reaction, in which number of moles are less, thus. in this reaction, increase in pressure favours the backward reaction.