Tin oxide (SnO₂) is amphoteric. This means it can act as both an acid and a base, depending on the conditions.

Here's why:

* As a base: Tin oxide can react with strong acids like hydrochloric acid (HCl) to form tin salts and water. For example:

SnO₂ + 2HCl → SnCl₂ + H₂O

* As an acid: Tin oxide can react with strong bases like sodium hydroxide (NaOH) to form stannate ions and water. For example:

SnO₂ + 2NaOH → Na₂SnO₃ + H₂O

The amphoteric nature of tin oxide is due to the ability of tin to exist in different oxidation states (+2 and +4) and the ability of oxygen to form both acidic and basic oxides.