Question

Le Chatelier's principle is not applicable for which of the following reaction?

• A. $H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$
• B. $Fe\left(s\right)+S\left(s\right)\rightleftharpoons FeS\left(s\right)$
• C. $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$
• D. $N_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2NO\left(g\right)$

Answer 1

The correct option is B $Fe\left(s\right)+S\left(s\right)\rightleftharpoons FeS\left(s\right)$

Le-Chatelier's principle is not applicable to solid-solid equilibrium.
Their concentration in the $K_{eq}$ expression is taken to be unity. So, no effect of pressure, volume, increasing or decreasing reactant, product species is there on the system.
Every other reaction has species which are in gaseous state.
thus Le-Chatelier's principle is applicable to all other three options except (b)