Question

The Reaction Quotient (Q) for the reaction $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$ is given by $Q=\frac{[N{H}_3{]}^2}{\left[N_2\right][H_2{]}^3}$, the reaction will shift in forward direction if :

• A. $Q=K_c$
• B. $Q<K_c$
• C. $Q>K_c$
• D. $Q=0$

Answer 1

The correct option is B $Q<K_c$

Given reaction is $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)Q=\frac{[N{H}_3{]}^2}{\left[N_2\right][H_2{]}^3}$
the equilibrium constant for this reaction is $K_c=\frac{[N{H}_3{]}^2}{\left[N_2\right][H_2{]}^3}$
$\Delta n=2-4=-2$
At equilibrium $Q=K_c$
So, the reaction will shift in forward direction if $Q<K_c$ or the concentration of the reactant is less than reactants