JEE Main · 2019 · Shift-IIeasyPB11-047

The number of pentagons in C60 and trigons (triangles) in white phosphorus, are:

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

Question

The number of pentagons in C60\mathrm{C_{60}} and trigons (triangles) in white phosphorus, are:

Options
  1. a

    12 and 3

  2. b

    20 and 4

  3. c

    20 and 3

  4. d

    12 and 4

Correct Answerd

12 and 4

Detailed Solution

Strategy: Count the pentagons in C₆₀ and the trigons (triangles) in white phosphorus.

Step 1: Pentagons in C₆₀ \ceC60\ce{C60} (Buckminsterfullerene) is a truncated icosahedron with 20 hexagons and 12 pentagons. Number of pentagons = 12.

Step 2: Trigons (Triangles) in White Phosphorus White phosphorus exists as discrete \ceP4\ce{P4} molecules. Each \ceP4\ce{P4} molecule is a tetrahedron with 4 triangular faces. Number of trigons = 4.

Step 3: Final Answer Pentagons in \ceC60\ce{C60} = 12; Triangles in white phosphorus = 4.

Answer: (D) 12 and 4\boxed{\text{Answer: (D) 12 and 4}}

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