1, SO3 + H2O -> H2SO4
2, P2O5 +H2O -> H3PO4
3, BaO + H2O -> Ba(OH)2
4, K2O + H2O -> 2KOH
5, Fe2O3 +3H2SO4 -> Fe2(SO4)3 + 3H2O
6, MgO + 2HCl -> H2O + MgCl2
7, CO2 + Ca(OH)2 -> CaCO3 + H2O
8, SO2 + NaOH -> Na2SO3 + H2O
9, Fe + HCl -> FeCl2 +H2
10, Cu + H2SO4 (loãng) ->  CuSO4 + H2O + SO4
11, Cu(OH)2 +2HCl -> 2H2O +CuCl2