8 g sample of KMnO4 is reacted in acidic medium with 100 ml of 10 volume H2O2.The % purity of KMnO4 sample is.?

KMnO4....+H2O2.....................>O2..+H₂O......+Mn2+..............(i)..(Unbalenced form)
10 volume H2O2means that If 1 litre of H2O2 solution is taken tgen it will liberate 10 litre of O2.
So we should calculte the number of moles of H2O2 in 100ml of this solution.
H2O2................>H2O....+1/2O_2.................(ii)
22.4 litre=1mole O2
10 litre=10/22.4 mole of O2
from ((ii), we can see that 1 mole of H2O2 will give ½ mole of O2
so for 10/22.4 mol O2 liberation, moles of H2O2 in the 1 litre solution must be 2*10/22.4 moles=Molarity of H2O2 solution.
[So we have molarity of the H2O2(moles of H2O2 per litre of solution)]
Now calculate moles of H2O2 in 100 ml of the solution=molarity*0.1
Now balence (i) by any of the method and then see how many moles of H2O2 is required for reacting with 1 mole of KMnO4 also, convert 8g into moles.
If you are getting any problem in balencing and further calculation in the % purity, you can post your doubt...

Dear Student, this method seems to be lengthy but it was for your understanding the basic concepts, not simply for the solving question; as your question require all the given in formation what I have written and
If your basics are good then you can have different types of approach.
However these types of question require basic concepts clear and just formula will not help you much.