200 ml of 0.01 M KMnO4 oxidise 20 ml of H2O2 sample in acidic medium. ...
200 ml of 0.01 M KMnO4 oxidise 20 ml of H2O2 sample in acidic medium. ...
Calculation
The balanced chemical equation for the reaction between KMnO4 and H2O2 in acidic medium is:
5H2O2 + 2MnO4- + 6H+ → 5O2 + 2Mn2+ + 8H2O
From the equation, we can see that 2 moles of KMnO4 react with 5 moles of H2O2. Therefore, the number of moles of H2O2 in the given sample can be calculated as follows:
Number of moles of H2O2 = (0.01 mol/L) x (0.2 L) x (5/2) = 0.005 mol
The volume strength of H2O2 is defined as the volume of oxygen (measured at STP) that can be liberated from 1 mL of the solution. From the equation, we can see that 5 moles of H2O2 produce 5 moles of O2. Therefore, the volume of oxygen liberated from the given sample can be calculated as follows:
Volume of O2 liberated = (0.005 mol) x (22.4 L/mol) = 0.112 L
The volume strength of H2O2 is then calculated as follows:
Volume strength of H2O2 = (0.112 L) / (0.02 L) = 5.6 volume
Therefore, the correct answer is option A, 2.8 volume.