JEE Main · 2021 · Shift-IhardGOC-091

Increasing order of basicity:

General Organic Chemistry (GOC) · Class 11 · JEE Main Previous Year Question

Question

Increasing order of basicity: image

Options
  1. a

    (A) < (B) < (C) < (D)

  2. b

    (D) < (A) < (B) < (C)

  3. c

    (B) < (A) < (C) < (D)

  4. d

    (B) < (A) < (D) < (C)

Correct Answerd

(B) < (A) < (D) < (C)

Detailed Solution

Step 1: Comparing Nitrogen Basicity Basicity depends on the availability of the nitrogen lone pair.

  • (C) Pyrrolidine: sp3sp^3 nitrogen, localized lone pair. Most basic.
  • (D) Imidazole: One nitrogen lone pair is localized (sp2sp^2), the other is aromatic. Still fairly basic as the sp2sp^2 nitrogen can accept a proton.
  • (A) Pyridine: sp2sp^2 nitrogen lone pair is localized but in a more electronegative orbital than sp3sp^3.
  • (B) Pyrrole: lone pair is involved in aromaticity (6π system). Least basic.

Step 2: Conclusion Order: (C) > (D) > (A) > (B).

Answer: (d) (B) < (A) < (D) < (C)\boxed{\text{Answer: (d) (B) < (A) < (D) < (C)}}

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