Consider the following gaseous equilibrium reactions (I), (II) and (III) with equilibrium constants $\mathrm{K}_1, \mathrm{~K}_2$ and $\mathrm{K}_3$ respectively I) $\frac{1}{2} \mathrm{~N}_2+\frac{3}{2} \mathrm{H}_2 \rightleftharpoons \mathrm{NH}_3$ II) $2 \mathrm{NO} \rightleftharpoons \mathrm{N}_2+\mathrm{O}_2$ III) $\mathrm{H}_2+\frac{1}{2} \mathrm{O}_2 \rightleftharpoons \mathrm{H}_2 \mathrm{O}$ The correct expression for the equilibrium constant for the gaseous equilibrium reaction $2 \mathrm{NH}_3+\frac{5}{2} \mathrm{O}_2 \rightleftharpoons 2 \mathrm{NO}+3 \mathrm{H}_2 \mathrm{O}$ is

• A

  $\frac{\mathrm{K}_3^2}{\mathrm{~K}_1 \times \mathrm{K}_2}$
• Correct answer
  B

  $\frac{\mathrm{K}_3^3}{\mathrm{~K}_1^2 \times \mathrm{K}_2}$
• C

  $\frac{\mathrm{K}_3^2}{\mathrm{~K}_1^2 \times \mathrm{K}_2}$
• D

  $\frac{\mathrm{K}_3}{\mathrm{~K}_1^{1 / 2} \times \mathrm{K}_2^2}$

Hence, the correct answer is option: 'B'.