Question

Which of the following statement for the equilibrium reaction $2N{H}_3\left(g\right)\rightleftharpoons N_2\left(g\right)+3H_2\left(g\right)$ are true?

• A. $K_p$ of the reaction is changed with increase in pressure of the system
• B. $K_p$ of the reaction remains unaffected with increase in pressure of the system
• C. More of $N{H}_3\left(g\right)$ is decreased with increase in pressure
• D. Less of $H_2\left(g\right)$ is formed as compared to $N_2\left(g\right)$

Answer 1

The correct option is B $K_p$ of the reaction remains unaffected with increase in pressure of the system

The equilibrium constant of a reaction is independent of pressure of the system. Since the reaction involves increase in the gaseous species, increasing pressure will favour the formation of more amount of $N{H}_3\left(g\right).$
$K_p=\frac{\left[N_2\right][H_2{]}^3}{\left[N{H}_3\right]}$
As per Le - chatelier principle,
when pressure is increased, reaction shift where the number of moles decreases. In this reaction, number of moles of product are more so reaction will shift towards the backward reaction.
Since, stoichiometry of the reaction gives that amount of $H_2$ formed will be more than amount of $N_2$.