Q3 / 75 · JEE Main 2025 (2 Apr Shift 1) · Chemistry

The correct order of basic nature on aqueous solution for the bases \(\mathrm{NH}_3, \mathrm{H}_2 \mathrm{~N}-\mathrm{NH}_2, \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2\), \(\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}\) and \(\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N}\) is :

  • A
    \(\mathrm{NH}_3 \lt \mathrm{H}_2 \mathrm{~N}-\mathrm{NH}_2 \lt \left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N} \lt \) \(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2 \lt \left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}\)
  • B
    \(\mathrm{NH}_3 \lt \mathrm{H}_2 \mathrm{~N}-\mathrm{NH}_2 \lt \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2 \lt \) \(\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH} \lt \left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N}\)
  • C
    \(\mathrm{H}_2 \mathrm{~N}-\mathrm{NH}_2 \lt \mathrm{NH}_3 \lt \left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N} \lt \) \(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2 \lt \left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}\)
  • Correct answer
    D
    \(\mathrm{NH}_2-\mathrm{NH}_2 \lt \mathrm{NH}_3 \lt \mathrm{CH}_3 \mathrm{CH}_2 \mathrm{NH}_2 \lt \) \(\left(\mathrm{CH}_3 \mathrm{CH}_2\right)_3 \mathrm{~N} \lt \left(\mathrm{CH}_3 \mathrm{CH}_2\right)_2 \mathrm{NH}\)

Solution

Basic strength of amine depends on hydrogen bonding and electronic inductive effect.
\(\mathrm{NH}(\mathrm{Et})_2 \gt \mathrm{N}(\mathrm{Et})_3 \gt \mathrm{NH}_2 \mathrm{Et} \gt \mathrm{\stackrel{\cdot \cdot}{N}H}_3 \gt \mathrm{NH}_2-\mathrm{NH}_2\)

Hence, the correct answer is option: 'D'.

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