JEE Main 2024ChemistryIonic EquilibriumHardNumerical

JEE Main 2024 — Ionic Equilibrium Question with Solution

JEE Main 2024 (30 Jan Shift 2)

Question

The pH of an aqueous solution containing 1M benzoic acid pKa=4.20 and 1M sodium benzoate is 4.5. The volume of benzoic acid solution in 300 mL of this buffer solution is __________mL.

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Show full solutionCorrect answer: 100
Correct answer
100

Step-by-step explanation

Benzoic acid+Sodium benzoateMolarity1M1MVolumeVamlVsmlmilli molesVa×1Vs×1

pH=4.5

pKa=4.20

pH=pKa+log[ salt ][ acid ]

4.5=4.2+logVsVaWhere,Vs- Volume of saltVa- Volume of acid

VsVa=2..........(i)

Vs+Va=300........(ii)

Va=100ml

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About this question

This is a previous-year question from JEE Main 2024, covering the Ionic Equilibrium 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.