Aqueous solutions of hydrogen peroxide sold in pharmacies are usually approximately 3% H2O2 by mass. However, in solution, hydrogen peroxide decomposes into water and oxygen. What is the percent by mass of a solution of hydrogen peroxide, H2O2, prepared from 2.104 g of H2O2 which is titrated with 51.78 cm3 of 0.03245 mol dm-3 KMnO4(aq). The reaction occurs in an acidified solution