JEE Main 2022ChemistryRedox ReactionsHardNumerical

JEE Main 2022 — Redox Reactions Question with Solution

JEE Main 2022 (28 Jun Shift 1)

Question

A 2.0 g sample containing MnO2 is treated with HCl liberating Cl2. The Cl2 gas is passed into a solution of KI and 60.0mL of 0.1MNaS2O3 is required to titrate the liberated iodine. The percentage of MnO2 in the sample is____. Nearest integer)
[Atomic masses (in u) Mn=55;Cl=35.5:O=16,I=127,Na=23,K=39,S=32]

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Show full solutionCorrect answer: 13
Correct answer
13

Step-by-step explanation

MnO2+4HCl⟶MnCl2+Cl2g+2H2O

Cl2+2Kl⟶I2+2KCl

I2+2Na2 S2O3⟶2Nal+Na2 S4O6

Mili eq. of MnO2= Mili eq. of Cl2= Mili eq. of I2= Mili eq. of Hypo.

2w87=0.1×60

W=261 miligram

% of MnO2=0.2612×100=13.05%≈13

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About this question

This is a previous-year question from JEE Main 2022, 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.