JEE Main · 2019 · Shift-ImediumPB11-007

C60, an allotrope of carbon contains

p-Block Elements (Class 11) · Class 11 · JEE Main Previous Year Question

Question

C60\mathrm{C_{60}}, an allotrope of carbon contains

Options
  1. a

    12 hexagons and 20 pentagons.

  2. b

    16 hexagons and 16 pentagons.

  3. c

    18 hexagons and 14 pentagons.

  4. d

    20 hexagons and 12 pentagons.

Correct Answerd

20 hexagons and 12 pentagons.

Detailed Solution

Strategy: Recall the structural composition of Buckminsterfullerene, \ceC60\ce{C60}.

Step 1: Ring Composition \ceC60\ce{C60} (Buckyball) has the structure of a truncated icosahedron:

  • 20 hexagonal (six-membered) rings
  • 12 pentagonal (five-membered) rings

Step 2: Rule of Fullerene Structures All five-membered rings are surrounded only by six-membered rings (no two pentagons are adjacent — this is the isolated pentagon rule). Each carbon is sp2sp^2 hybridised with a delocalised π\pi system.

Answer: (D) 20 hexagons and 12 pentagons\boxed{\text{Answer: (D) 20 hexagons and 12 pentagons}}

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