The volume of 40 vol. H2O2 solution required to prepare 2L. of O2 at STP is

40 volume strength of H2O2 solution means,1ml of H2O2 solution   →gives  40 ml of "O2"??     of H2O2 solution →gives2L=2000ml 0f O22000ml×1ml40ml= 50ml of H2O2 solution50ml of 40 vol strength of H2O2 solution at STP produces 2L (or) 2000ml of O2 .