Assertion : $\mathrm{Cu}(\mathrm{OH})_2$ is soluble in $\mathrm{NH}_4 \mathrm{OH}$ but not in $\mathrm{NaOH}$. Reason : $\mathrm{Cu}(\mathrm{OH})_2$ forms a soluble complex with $\mathrm{NH}_3$.

• 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'.