(a) H2O is prepared by acidifying barium peroxide and removing excess water by evaporation under reduced pressure.
BaO2 .8H2O(s) + H2SO2 (aq) → BaSO4 (s) + H2O2 (aq) + 8H2O(I)
(b) A 30% solution of H2O2 is called 100 volume H2O . It means that one mL of 30% H2O2 solution will give 100 V of oxygen at STP.
c) H2O2 is has non-planar structure as shown below: