What is the equilibrium expression for the reaction $\mathrm{P}_{4(\mathrm{~s})}+5 \mathrm{O}_{2(\mathrm{~g})} \rightleftharpoons \mathrm{P}_4 \mathrm{O}_{10(\mathrm{~s}}$ ?

• A

  $\left.\mathrm{Kc}=\left[\mathrm{P}_4 \mathrm{O}_{10}\right] / \mathrm{P}_4\right]\left[\mathrm{O}_2\right]^5$
• Correct answer
  B

  $\mathrm{Kc}=1 /\left[\mathrm{O}_2\right]^5$
• C

  $\mathrm{Kc}=\left[\mathrm{O}_2\right]^5$
• D

  $\mathrm{Kc}=\left[\mathrm{P}_4 \mathrm{O}_{10}\right] / 5\left[\mathrm{P}_4\right]\left[\mathrm{O}_2\right]$

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