Question

Using

0.200 ml H2O2

10 mL H2SO4 (aq) 1 M

Solution titrated with KMnO4(aq) 0.20M

In the reaction of the redox pairs MnO4- | Mn2+ and H2O2 | O2. Show reaction scheme and calculate the formal concentration c(H2O2)

35% h2o2 and density=1.126 g/ml

Answer 1

The balanced reaction is given by

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

given H2O2 is 35 %

hence H2O2 volume in ml = (35/100) x H2O2 solution

       = ( 35/100) x 0.2 = 0.07 ml

Mass of H2O2 = volume x density = 0.07 ml x 1.126 g/ml = 0.07882 g

Moles of H2O2 = mass / Molar mass of H2O2 = 0.0788 /34 = 0.00232

Molarity of H2O2 = mole sof H2O2 / solution volume in L

solution volume = 0.2 ml + 10 ml = 10.2 ml = 0.0102 L

hence C ( H2O2) = ( 0.00232 /0.0102) = 0.227 M