JAMB - Chemistry (2024 - No. 77)
An example of an amphoteric oxide is
P\(_4\)O\(_{10}\)
Al\(_2\)O\(_3\)
CuO
K\(_2\)O
Paaiškinimas
Amphoteric oxides are metal oxides that can behave as both acidic and basic oxides. They react with acids and bases to produce water and salts. When dissolved in water, amphoteric oxides form alkaline solutions that contain hydroxide ions. E.g ZnO, Al\(_2\)O\(_3\),PbO etc
The chemical reactions
Al\(_2\)O\(_3\) + 6HCl → 2AlCl\(_3\) + 3H\(_2\)O and 
Al\(_2\)O\(_3\) + 2NaOH → 2NaAlO\(_2\) + H\(_2\)O show that 
Al\(_2\)O\(_3\) is amphoteric.