Chemistry - Redox Reactions Question with Solution | TestHub

ChemistryRedox ReactionsMiscellaneous/MixedEasy2 minPYQ_2020
ChemistryEasynumerical

Hydrogen peroxide solution (20 mL) reacts quantitatively with a solution of KMnO4(20 mL) acidified with dilute H2SO4. The same volume of the KMnO4solution is just decolourised by 10 mL of MnSO4in neutral medium simultaneously forming a dark brown precipitate of hydrated MnO2.The brown precipitate is dissolved in 10 mL of 0.2 M sodium oxalate under boiling condition in the presence of dilute H2SO4. Write the balanced equations involved in the reactions and calculate the molarity of H2O2.

Answer:
0.10
Solution:

I  2KMn O 4 + 3 H 2 S O 4 + 5 H 2 O 2 K 2 S O 4 + 2 Mn S O 4 + 8 H 2 O + 5 O 2

I I  2KMn O 4 + 3 Mn S O 4 + 2 H 2 O 5 Mn O 2 + K 2 S O 4 + 2 H 2 S O 4

I I I  Mn O  2 + Na 2 C 2 O 4 + 2 H 2 S O 4 Mn S O 4 + Na 2 S O 4 + 2 CO 2 + H 2 O

Reaction (III) mM of Na 2 C 2 O 4 = 10 mL × 0.2M = 2 mM = mM  of  Mn O 2

Reaction (II) mM of   K MnO 4 = 2 × 2 5 = 4 5 mM

Reaction (I) mM of    H 2 O 2 = 4 5 × 5 2 = 2 mM

2 mM of H 2 O 2 = 20 mL × M H 2 O 2

M H 2 O 2 = 0.1 M

Stream:NTA_ABHYASSubject:ChemistryTopic:Redox ReactionsSubtopic:Miscellaneous/Mixed
2mℹ️ Source: PYQ_2020

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