what are amphoteric acids? give examples.

Amphoteric substances are those which show both acidic and basic nature. Example: Al2O3 , ZnO

Amphoteric acids are those acids which show both acidic and basic nature.Example is amino acids.

Amino acids have both acidic and basic centers so when they react with an acid behave just like a Lewis base (accept the hydrogen ion) and when react with a base behave as an acid so amino acids show dual nature.