In transforming 0.01 mole of PbS to PbSO4 the volume of 10 volume H2O2 required is

PbS+4H2O2→PbSO4+4H2O4H2O2→4H2O+2O2 4 x 34                    2 mole                              2 x 22.4 litre at STP = 44.8For 1 mole of PbS     -----------   44.8  lit of O2 at STP is required  0.01 mole of PbS      -----------   0.448 lit of O2 at STP is required              Volume of O2 at STP = Volume in ml x volume strength                           448 ml          = Volume in ml x 10                        Volume in ml  = 44810=44.8  ml