11. :: Water can act as an acid or a base, as it is amphoteric . 12. Aluminum hydroxide is amphoteric in character: 13. Most alkaloids are weak bases, but some, such as theobromine and theophylline, are amphoteric . 14. Some ions are classed as amphoteric , being able to react with either an acid or a base. 15. Germanium forms an amphoteric oxide, GeO 2 and anionic germanates, such as Mg 2 GeO 4. 16. The oxide in its preferred oxidation state ( Sb 2 O 3, + 3 ) is amphoteric . 17. There are also special columns that have resins with amphoteric functional groups that can exchange both cations and anions. 18. It bonds covalently in most of its compounds; has an amphoteric oxide; and can form anionic aluminates. 19. Its crystalline structure shows some evidence of Al 2 O 3 is amphoteric , and a conditional glass-former. 20. Water is amphoteric , meaning it is both an acid and a base it produces and ions by self ionization.
