If 30cm3 of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm3 of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively?

  • A 9.3 sec
  • B 14 sec
  • C 21 sec
  • D 28 sec
  • E 30.3 sec
jamb 1978chemistry

The correct answer is C. 21 sec

The rate of diffusion of a gas is proportional to the square root of the density.

16 and 7 secs

36 or 6 will be proportional to

7/16 x 6

7/4 x 6

But volume of chlorine is twice that of oxygen. The rate of escape of chlorine is

2/1 x 7/4 x 6/1 = 7 x 3; = 21 sec

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