Question

At constant pressure, addition of helium to the reaction system :
$\left(\text{N}\right)_{\text{2}} \left(\text{(g) + 3H}\right)_{\text{2}} \text{(g) } \rightleftharpoons \left(\text{2NH}\right)_{\text{3}} \text{(g)}$

• A. Favours the formation of ammonia
• B. Reduces the formation of ammonia
• C. Does not affect the position of equilibrium
• D. Reduces the dissociation of ammonia.

Answer 1

Answer: (B)

$K_{p} \, =\frac{\left(n^{2}\right)_{N H_{3}}}{n_{N_{2}} \times n_{H_{2}}^{3}}\times \, \left(\frac{P}{\Sigma n}\right)^{\Delta n}$
At constant pressure, with the introduction inert gas $\Sigma n$ increases. Since $\Delta n=-2$ , therefore on increasing $\Sigma n \, \left(\frac{P}{\Sigma n}\right)^{\Delta n}$ increases, but $K_{p}$ remain constant, hence no. of
moles of $N_{2} \, \left(g\right)$ & $H_{2} \, \left(g\right)$ are increased and backward reaction is favoured.