## General Chemistry: Principles and Modern Applications (10th Edition)

$HNO_2(aq) + H_2O(l) N{O_2}^-(aq) + H_3O^+(aq)$ Therefore: $HNO_2$ = Acid. ${PO_4}^{3-}(aq) + H_2O(l) {HPO_4}^{2-}(aq) + OH^-(aq)$ Therefore: ${PO_4}^{3-}$ = Base. $H{CO_3}^-(aq) + H_2O(l) {CO_3}^{2-}(aq) + H_3O^+(aq)$ $H{CO_3}^-(aq) + H_2O(l) H_2{CO_3}(aq) + OH^-(aq)$ Therefore: $H{CO_3}^-$ = Amphiprotic.
Remember that acids are molecules that are capable of donating one proton. ($H{CO_3}^-$ and $HNO_2$) And bases are molecules capable of receiving one proton. ($H{CO_3}^-$ and ${PO_4}^{3-}$) - Amphiprotic are species that can either receive or donate a proton.