JEE Main 2023ChemistryRedox ReactionsMediumNumerical

JEE Main 2023 — Redox Reactions Question with Solution

JEE Main 2023 (13 Apr Shift 1)

Question

20 mL of calcium hydroxide was consumed when it was reacted with 10 mL of unknown solution of H2SO4. Also 20 mL standard solution of 0.5 M HCl containing 2 drops of phenolphthalein was titrated with calcium hydroxide, the mixture showed pink colour when burette displayed the value of 35.5 mL whereas the burette showed 25.5 mL initially. The concentration of H2SO4 is _______M. (Nearest integer)

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Correct answer
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Step-by-step explanation

Titration principle is N1V1=N2V2

N = Normality

V = Volume of solution

M1V1n1=M2V2n2

M = molarity

n = Valence factor of acid or base

As pink colour is obtained on consumption of 10 ml of Ca(OH)2, we have

20×0.5×1=10×M×2

Molarity of Ca(OH)2=1020=12M

Also, moles of Ca(OH)2=mm of H2SO4

12×20=10×M

Molarity of H2SO4=1M

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About this question

This is a previous-year question from JEE Main 2023, 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.