for instance zinc(II), which dissolves in base, from manganese(II), which does not dissolve in base.

Lead oxide (PbO):
* PbO + \overset{acid}{2 HCl} -> PbCl2 + H2O
* PbO + \overset{base}{2 NaOH} + H2O -> Na2[Pb(OH)4]

Lead oxide :
* PbO2 + \overset{acid}{4 HCl} -> PbCl4 + 2H2O
* PbO2 + \overset{base}{2 NaOH} + 2H2O -> Na2[Pb(OH)6]