Acid strength given below the… - JEE Main 2019 Chemistry PYQ

JEE Main 2019 — Chemistry Organic Chemistry

2019mcqeasy

Acid strength given below the correct decreasing order will be :

Official previous-year question

Held on 9 Jan 2019 · Verified 6 Jul 2026.

Options

A
${\mathrm{NO}}_{2}{\mathrm{CH}}_{2}\mathrm{COOH}>{\mathrm{FCH}}_{2}\mathrm{COOH}>{\mathrm{CNCH}}_{2}\mathrm{COOH}>{\mathrm{ClCH}}_{2}\mathrm{COOH}$
B
${\mathrm{NO}}_{2}{\mathrm{CH}}_{2}\mathrm{COOH}>{\mathrm{NCCH}}_{2}\mathrm{COOH}>{\mathrm{FCH}}_{2}\mathrm{COOH}>{\mathrm{ClCH}}_{2}\mathrm{COOH}$
C
${\mathrm{CNCH}}_{2}\mathrm{COOH}>{O}_{2}{\mathrm{NCH}}_{2}\mathrm{COOH}>{\mathrm{FCH}}_{2}\mathrm{COOH}>{\mathrm{ClCH}}_{2}\mathrm{COOH}$
D
${\mathrm{FCH}}_{2}\mathrm{COOH}>{\mathrm{NCCH}}_{2}\mathrm{COOH}>{\mathrm{NO}}_{2}{\mathrm{CH}}_{2}\mathrm{COOH}>{\mathrm{ClCH}}_{2}\mathrm{COOH}$

Did you get this right?

Solution

Acidic character $\alpha$ stability of conjugate base (anion)

Stability of anion $\alpha –I$

Hence greater the $–I$ effect greater will be the acidity

Order of -I-effect $-{\mathrm{NO}}_{2}>\mathrm{CN}>-F>-\mathrm{Cl}$ Hence, order of acidity will be

$\begin{matrix}{O}_{2}{\mathrm{NCH}}_{2}\mathrm{COOH}>\mathrm{NC} {\mathrm{CH}}_{2}\mathrm{COOH}>{\mathrm{FCH}}_{2} \mathrm{COOH}>\mathrm{Cl} {\mathrm{CH}}_{2} \mathrm{COOH} \\ \end{matrix}$

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Options

${\mathrm{NO}}_{2}{\mathrm{CH}}_{2}\mathrm{COOH}>{\mathrm{FCH}}_{2}\mathrm{COOH}>{\mathrm{CNCH}}_{2}\mathrm{COOH}>{\mathrm{ClCH}}_{2}\mathrm{COOH}$

${\mathrm{NO}}_{2}{\mathrm{CH}}_{2}\mathrm{COOH}>{\mathrm{NCCH}}_{2}\mathrm{COOH}>{\mathrm{FCH}}_{2}\mathrm{COOH}>{\mathrm{ClCH}}_{2}\mathrm{COOH}$

${\mathrm{CNCH}}_{2}\mathrm{COOH}>{O}_{2}{\mathrm{NCH}}_{2}\mathrm{COOH}>{\mathrm{FCH}}_{2}\mathrm{COOH}>{\mathrm{ClCH}}_{2}\mathrm{COOH}$

${\mathrm{FCH}}_{2}\mathrm{COOH}>{\mathrm{NCCH}}_{2}\mathrm{COOH}>{\mathrm{NO}}_{2}{\mathrm{CH}}_{2}\mathrm{COOH}>{\mathrm{ClCH}}_{2}\mathrm{COOH}$

Solution

Acidic character $\alpha$ stability of conjugate base (anion)

Stability of anion $\alpha –I$

Hence greater the $–I$ effect greater will be the acidity

Order of -I-effect $-{\mathrm{NO}}_{2}>\mathrm{CN}>-F>-\mathrm{Cl}$ Hence, order of acidity will be

$\begin{matrix}{O}_{2}{\mathrm{NCH}}_{2}\mathrm{COOH}>\mathrm{NC} {\mathrm{CH}}_{2}\mathrm{COOH}>{\mathrm{FCH}}_{2} \mathrm{COOH}>\mathrm{Cl} {\mathrm{CH}}_{2} \mathrm{COOH} \\ \end{matrix}$

Options

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Solution

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Options

Did you get this right?

Solution

Your note

JEE Main Organic Chemistry in other years

More JEE Main Organic Chemistry questions

Other Chemistry topics for JEE Main

Physical Chemistry

Inorganic Chemistry

Keep practicing Organic Chemistry