A reaction occurs between 3 moles of H2 and 1.5 moles of O2 to give some amount of H2O. The limiting reagent in this reaction is

H2+12O2 → H2OInitial mol ratio of H2 / O2 = 2:1Mol ratio required in the reaction = 3/1.5 = 2:1Since the mol ratio is same, so none is the limiting reagent