Hydrogen peroxide in aqueous solution decomposes on  warming to given oxygen according to the equation,2H2O2(aq)⟶2H2O(l)+O2(g)Under conditions where 1 mol of gas occupies 24 dm3, 100 cm3  of X M solution of H2O2, produces 3 dm3 of O2. Thus, X is

(n factor for O2= 4) Volume strength of H2O2 = 244=6L6 'VS' of H2O2 = 1 NH2O26 'VS' of H2O2 x Vol of H2O2 = Vol of O2'VS'of  H2O2 x 100 cm3 = 3 dm3'VS'of H2O2 x 0.1 dm3 =3dm3'VS' of H2O2 = 30 dm3 or L6 'VS' of H2O2 = 1 N 30 ‘VS’ of H2O2 = 1×306=5NM = 5/2 = 2.5