:
* Al2O3 + \overset{acid}{6 HCl} -> 2 AlCl3 + 3 H2O
* Al2O3 + \overset{base}{2 NaOH} + 3 H2O -> 2 Na[Al(OH)4] (hydrated sodium aluminate)

Stannous oxide (SnO):
* SnO + \overset{acid}{2 HCl} <=> SnCl2 + H2O
* SnO + \overset{base}{4 NaOH} + H2O <=> Na4[Sn(OH)6]

Stannic oxide :
* SnO2 + \overset{acid}{4 HCl} <=> SnCl4 + 2H2O