The metal hydroxide which is soluble in excess of ammonium hydroxide is

• A

  $\mathrm{Fe}(\mathrm{OH})_{2}$
• B

  $\mathrm{Fe}(\mathrm{OH})_{3}$
• Correct answer
  C

  $\mathrm{Cu}(\mathrm{OH})_{2}$
• D

  $\mathrm{Al}(\mathrm{OH})_{3}$

Solution

Copper (II) hydroxide $\left[\mathrm{Cu}(\mathrm{OH})_{2}\right]$ is amphoteric in nature and is soluble in excess of ammonium hydroxide.

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