Question
What is the mass of hydrogen peroxide present in 1 litre of 2M solution? Calculate the volume of oxygen at STP liberated upon the complete decomposition of 100 cm3 of the above solution.
Solution
(i) To calculate the mass of H2O2 in 1 litre of 2 M solution:
Moleuclar mass of H2O2 = 2 x 1 + 2 x 16 = 34 amu
Now 1 litre of 1 M solution contains
H2O2 = 34 g
(ii) To calculate the volume of O2 liberated at STP from 1000 cm3 of 2M solution:
Decomposition of H2O2 can be represented as:
Now 68 g of 
at S.T.P. given O2 = 22400 cm3
