JEE Main 2020ChemistryRedox ReactionsMediumNumerical

JEE Main 2020 — Redox Reactions Question with Solution

JEE Main 2020 (04 Sep Shift 1)

Question

A 20.0 mL solution containing 0.2 g impure H2O2 reacts completely with 0.316 g of KMnO4 in acid solution. The purity of H2O2 (in %) is______  (mol. wt. of H2O2=34; mol. wt. of KMnO4=158)

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Show full solutionCorrect answer: 85
Correct answer
85

Step-by-step explanation

Let mass of pure H2O2 is x gram

+7MnO4−  +  −1H2O2vf=2   →   +2Mn2+ +  0O2

Eq. of H2O2=Eq. of MnO4-

x342=0.316158 5

x=0.17

So, % purity of H2O2 solution =0.170.2×100=85%

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About this question

This is a previous-year question from JEE Main 2020, covering the Redox Reactions chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.