On hydrolysis, alkali metal oxides give the corresponding metallic hydroxides. Li2O+H2O⟶2LiOH Na2O+H2O⟶2NaOH The peroxides of alkali metals give the corresponding metallic hydroxide and H2O2
Na2O2+2H2O⟶2NaOH+H2O2
Whereas, the superoxide's of alkali metals give the corresponding metallic hydroxide, H2O2 and O2
2NaO2+2H2O⟶2NaOH+H2O2+O2
Be(OH)2 cannot be prepared by hydrolysis of BeO, as it is insoluble in water.