A1.00 g sample of a hydrogen peroxide (h2o2) solution is placed in an erlenmeyer flask and diluted with 20 ml of 1 m aqueous sulfuric acid. to this solution is added 0.0200 m kmno4 solution via a buret, until a pale purple color persists. this requires 22.50 ml of kmno4 solution. what is the percent by mass of hydrogen peroxide in the original solution?

Following reaction is involved in present system:

2KMnO4  +  5H2O2 +  3H2SO4 →  2MnSO4    +     K2SO4  + 5O2  +   8H2O

From the above balance reaction, it can be seen that 2 moles of KMnO4 is consumed for every 5 moles of H2O2.

 Now, percent by mass of hydrogen peroxide in the original solution can be estimated as follows:
percent by mass = 
∴percent by mass = 
                             = 4 % 

The correct answer should be "electrons orbit the nucleus in circular motions exactly as shown on the classic bohr model."