Question

Which is the set of amphiprotic species?

• A. $H_3{O}^{+},HP{O}_4^{2-},HC{O}_3^{-}$
• B. $H_{2}O,HP{O}_3^{2-},H_{2}P{O}_2^{-}$
• C. $H_{2}P{O}_4^{-},H_{2}P{O}_3^{-},H_{2}O$
• D. All of these

Answer 1

The correct option is C $H_{2}P{O}_4^{-},H_{2}P{O}_3^{-},H_{2}O$

A species that has the potential to act both as an acid by donating $H^{+}$ and as a base by accepting $H^{+}$ according to bronsted - lowry theory is said to be amphiprotic.
$H_3{O}^{+}$ can't accept $H^{+}$ more. So it can't act as base. Consequently aren't considered as amphiprotic species.
$HP{O}_3^{-2}$ and $H_{2}P{O}_2^{-}$ can't donate $H^{+}$ any more. So, they can't act as acid and consequently aren't considered as amphiprotic species.