JEE Main 2023ChemistryIonic EquilibriumHardNumerical

JEE Main 2023 — Ionic Equilibrium Question with Solution

JEE Main 2023 (25 Jan Shift 1)

Question

A litre of buffer solution contains 0.1 mole of each of NH3 and NH4Cl. On the addition of 0.02 mole of HCl by dissolving gaseous HCl, the pH of the solution is found to be _____×10-3 (Nearest integer)

Given: pKbNH3=4.745

log 2=0.301

log 3=0.477

T=298 K]

Enter your answer

Show full solutionCorrect answer: 9079
Correct answer
9079

Step-by-step explanation

In resultant solution after addition of HCl to the basic buffer:

nNH3=0.1-0.02=0.08

nNH4Cl=nNH4+=0.1+0.02=0.12

Using Henderson-Hasselbach equation:

pOH=pKb+logNH4+NH3

=4.745+log0.120.08

=4.745+log32

=4.745+0.477-0.301

pOH=4.921
We know,

pH=14-pH

=9.079

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About this question

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