## Chemistry: The Molecular Science (5th Edition)

$H_2O$ is an amphiprotic substance.
$H_2O$ can either donate a proton, becoming $OH^-$, or receive a proton, becoming $H_3O^+$; You can also analyze the table $14.2$ (Page 624), and see that, $H_2O$ has a $K_a$ and a $K_b$ value, which is a characteristic of amphiprotic substances.