Which of the following is an amphoteric hydroxide?
- Mg(OH)2
- Be(OH)2
- Sr(OH)2
- Ca(OH)2
Answer
(2) Be(OH)2
Solution
As per NCERT, beryllium shows anomalous behaviour; its oxide and hydroxide are amphoteric, while those of the other alkaline earth metals are basic.
Be(OH)2 + 2OH- [Be(OH)4]2-
Be(OH)2 + 2HCl + 2H2O [Be(OH2)4]Cl2
Be(OH)2 reacts with both acid and alkali.
Answer: (2)