Hydrogen combines with oxygen to form two compounds namely, water and hydrogen peroxide. Hydrogen + Oxygen ⟶ Water  Hydrogen + Oxygen ⟶ Hydrogen peroxide Here, the masses of oxygen which combine with a fixed mass of hydrogen bear simple ratio will be

In H2ORelation by mass  Hydrogen + Oxygen ⟶ Water                                    2g               16g   → 18 gInH2O2 Hydrogen + Oxygen ⟶ Hydrogen peroxide.          2g               32 g  →Hence, ratio of masses of oxygen in H2O  and H2O2                                                     = 16.32 i.e.(1 : 2)