Amphoteric behaviour is shown by

Options

A. `H_(2)CO_(3)` and `AI_(2)O_(3)`
B. `HCO_(3)^(-)` and `H_(2)O`
C. `HCO_(3)^(-)` and `H_(3)O^(+)`
D. `H_(2)CO_(3)` and `H_(2)O`

Answer

B

Explanation

Amphoteric behaviour is that any species which acts as an acid as well as base.
`underset("Acid")(HCO_(3)^(-)) rarr CO_(3)^(2-)+H^(+)`
`underset("Base")(HCO_(3)^(-)) +H^(+) rarr H_(2)CO_(3)`
`underset("Acid")(H_(2)O) rarr OH^(-) +H^(+)`
`underset("Base")(H_(2)O)+H^(+) rarr H_(3)O^(+)`