JEE MAIN - Chemistry (2023 - 25th January Evening Shift - No. 3)
Match List I with List II
| List I (Amines) | List II ($$\mathrm{pK_b}$$) | ||
|---|---|---|---|
| A. | Aniline | I. | 3.25 |
| B. | Ethanamine | II. | 3.00 |
| C. | N-Ethylethanamine | III. | 9.38 |
| D. | N, N-Diethylethanamine | IV. | 3.29 |
Choose the correct answer from the options given below :
Explanation
Aromatic amines are less basic than aliphatic amines. Among given aliphatic amines, $2^{\circ}$ amine is most basic, followed by $3^{\circ}$ amine and $1^{\circ}$ amine. Therefore the correct basic strength $\left(\mathrm{K}_{\mathrm{b}}\right)$ order of the given amines is
$$ \underset{(C)}{\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NHCH}_2 \mathrm{CH}_3}>\underset{(D)}{\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N}}>\underset{(B)}{\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2}>\underset{(A)}{\mathrm{C}_6 \mathrm{H}_5 \mathrm{NH}_2} $$
The $\mathrm{pK}_{\mathrm{b}}$ order of the given amines will be just the opposite of their basic strength order. The correct matching is
$A-I I I, B-I V, C-I I, D-I$
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