Amphoteric Oxides & Hydroxides
Sort oxides: amphoteric or basic?
Setting up the bench…
What this lesson covers
Why it matters
Most metal oxides are basic — they react only with acids. But a special few dissolve in BOTH acids and alkalis. Those are amphoteric.
Predict first
What makes an oxide amphoteric?
Amphoteric oxides and hydroxides (ZnO, Al₂O₃, PbO) react with both acids and alkalis. Basic oxides (CuO, MgO, Na₂O) react only with acids.
- It reacts with both acids and alkalis — correct
- It reacts only with acids
- It does not react with anything
What you do
Sort each oxide: amphoteric (reacts with acids AND alkalis) or basic (acids only).
Check yourself
Which oxide dissolves in sodium hydroxide solution?
ZnO is amphoteric and dissolves in alkali; CuO and MgO are basic (react with acids only).
Aluminium oxide reacts with BOTH dilute HCl and NaOH. This shows it is…
Reacting with both an acid and an alkali is the definition of amphoteric.
- ZnO — correct
- CuO
- MgO
- amphoteric — correct
- purely basic
- neutral