In which of the following reactions, $\mathrm{O}_2$ is not liberated?

• A

  $\mathrm{MnO}_4^{-}+\mathrm{H}_2 \mathrm{O}_2+\mathrm{H}^{+} \longrightarrow$
• B

  $\mathrm{H}_2 \mathrm{O}_2+\mathrm{I}_2+\mathrm{OH}^{-} \longrightarrow$
• C

  $\mathrm{HOCl}+\mathrm{H}_2 \mathrm{O}_2 \longrightarrow$
• Correct answer
  D

  $\mathrm{Fe}^{2+}(\mathrm{aq})+\mathrm{H}^{+}(\mathrm{aq})+\mathrm{H}_2 \mathrm{O}_2 \longrightarrow$

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