JEE Main 2023 — Chemistry Physical Chemistry

2023integermedium

$20\mathrm{mL}$ of $0.1\mathrm{MNaOH}$ is added to $50\mathrm{mL}$ of $0.1M$ acetic acid solution. The $\mathrm{pH}$ of the resulting solution is $\times {10}^{-2}$ . (Nearest integer) Given : $\mathrm{pK}a({\mathrm{CH}}_{3}\mathrm{COOH})=4.76$

$\mathrm{log}2=0.30$

$\mathrm{log}3=0.48$

Official previous-year question

Held on 13 Apr 2023 · Verified 6 Jul 2026.

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Solution

When a strong base is added to a weak acid solution, it results in the formation of a salt. Here, acid is present in a limiting reagent and base is present in excess amounts. So, by using the pH formula:

$\begin{matrix}\mathrm{pH} & = & \mathrm{pKa}+\mathrm{log}\frac{[\mathrm{salt}]}{[\mathrm{acid}]}\end{matrix}$

${\mathrm{CH}}_{3}\mathrm{COOH}+\mathrm{NaOH}\longrightarrow {\mathrm{CH}}_{3}\mathrm{COONa}+{H}_{2}O 52—— 302$

$\mathrm{pH}={\mathrm{pK}}_{a}+\mathrm{log}(\frac{2}{3})$

$\mathrm{pH}=4.76+0.30-0.48$

$=4.76–.18$

$=4.58$

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JEE Main 2023 — Chemistry Physical Chemistry

2023integermedium

$\mathrm{log}2=0.30$

$\mathrm{log}3=0.48$

Official previous-year question

Held on 13 Apr 2023 · Verified 6 Jul 2026.

Did you get this right?

Solution

$\begin{matrix}\mathrm{pH} & = & \mathrm{pKa}+\mathrm{log}\frac{[\mathrm{salt}]}{[\mathrm{acid}]}\end{matrix}$

${\mathrm{CH}}_{3}\mathrm{COOH}+\mathrm{NaOH}\longrightarrow {\mathrm{CH}}_{3}\mathrm{COONa}+{H}_{2}O 52—— 302$

$\mathrm{pH}={\mathrm{pK}}_{a}+\mathrm{log}(\frac{2}{3})$

$\mathrm{pH}=4.76+0.30-0.48$

$=4.76–.18$

$=4.58$

Your note

JEE Main Physical Chemistry in other years

Keep practicing Physical Chemistry

Work through every JEE Main Physical Chemistry PYQ, year by year.

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JEE Main 2023 — Chemistry Physical Chemistry

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Solution

Your note

JEE Main Physical Chemistry in other years

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Organic Chemistry

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JEE Main 2023 — Chemistry Physical Chemistry

Did you get this right?

Solution

Your note

JEE Main Physical Chemistry in other years

More JEE Main Physical Chemistry questions

Other Chemistry topics for JEE Main

Organic Chemistry

Inorganic Chemistry

Keep practicing Physical Chemistry