Q. Which compound is amphoteric (can act as both an acid and a base)?
✅ Correct Answer: (C)
Al(OH)3
Explanation: Aluminum hydroxide Al(OH)3 can react with acids (acting as a base) and with strong bases (acting as an acid) to form aluminate ions — that's amphoteric behavior. NaOH is purely basic, HCl is purely acidic, and CH4 (methane) is neither acidic nor basic in aqueous chemistry context. Therefore Al(OH)3 is correct.
Explanation by: Sikhar Chaudhary
Aluminum hydroxide Al(OH)3 can react with acids (acting as a base) and with strong bases (acting as an acid) to form aluminate ions — that's amphoteric behavior. NaOH is purely basic, HCl is purely acidic, and CH4 (methane) is neither acidic nor basic in aqueous chemistry context. Therefore Al(OH)3 is correct.