Question

In which of the following equilibrium reactions the equilibrium would shift to the left, if total pressure is increased?

• A. $N_2\left(g\right)$ + $3H_2\left(g\right)$ $\rightleftharpoons$ $2N{H}_3\left(g\right)$
• B. $PC{l}_5\left(g\right)\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$
• C. $H_2\left(g\right)$ + $C{l}_2\left(g\right)$ $\rightleftharpoons$ $2HCl\left(g\right)$
• D. $N_2{O}_4\left(s\right)$ $\rightleftharpoons$ $2NO\left(g\right)$

Answer 1

Answer: (B), (D)

$N_2{O}_4\left(s\right)$ $\rightleftharpoons$ $2NO\left(g\right)$

According to Le-Chatelier principle if any change happen in any component then the equilibirium is going to shift that direction where this change can be neutralize.
When we increased the total pressure of the system, the equilibirium will shift in such a direction where the number of gaseous atoms are less.
Both (b) and (d) has less gaseous molecules in the reactant side so on increasing the pressure, the equilibrium will shift to the left in (b) and (d) reaction.