What mass of hydrogen peroxide will be present in 2 litres of a 5 molar solution? Calculate the mass of oxygen which will be liberated by the decomposition of 200 mL of this solution.

Given, V = 2L and Molarity = 5M


We know that Molar mass of H2O2 = 34g


Molarity (M) =


=


5 =


W= 340g


Therefore, mass of hydrogen peroxide will be present in 2 litres of a 5 molar solution is 340g.


Mass of oxygen which will be liberated by the decomposition of 200 mL of this solution can be calculated as shown below.


No. of moles =


Molar volume = volume at STP = 22.4 L or 22400ml


No. of moles = = 0.0089


2H2O2 → 2H2O + O2


From the above equation it is clear that,


2 moles of H2O2 → 1 mole of O2


0.0089 moles of H2O2 → moles of O2


Now, we know mass = no. of moles of O2 × molecular mass of O2


= = 0.15g


Mass of oxygen which will be liberated by the decomposition of 200 mL of this solution is 0.15g.


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