Assertion : Sulphur is oxidised by $\mathrm{H}_2 \mathrm{O}_2$ in presence of $\mathrm{Fe}$ (III). Reason : Fe (III) oxidises sulphur to sulphate.

• Correct answer
  A

  If both assertion and reason are true and reason is the correct explanation of assertion.
• B

  If both assertion and reason are true but reason is not the correct explanation of assertion.
• C

  If assertion is true but reason is false.
• D

  If both assertion and reason are false.

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