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The van der Waal's constant 'b' of a gas is 4 π × 1 0 - 4 L/mol . How near can the centres of the two molecules approach each other ? [Use : N A = 6 × 10 23 ]

Options

  1. A1 0 - 7 m
  2. B1 0 - 10 m
  3. C5 × 1 0 - 1 1 m
  4. D5 × 1 0 - 9 m

Correct answer

B. 1 0 - 10 m

Step-by-step solution

b = 4 × 4 3 × π r 3 × N A ; We know that, 1 L = 1000 cm 3 4 × π × 1 0 - 4 × 1 0 0 0 = 4 × 4 3 × π × r 3 × 6 × 1 0 2 3 r = 5 × 1 0 - 9 cm Distance of closest approach = 2 r = 1 0 - 8 cm or 1 0 - 10 m

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