Question

BASIC CONCEPTS OF CHEMISTRY
(CLASS 11)

Equal moles of hydrogen and oxygen gases are placed in a container with a pinhole through which both can escape.

what fraction of the oxygen escapes in the time required for one half of the hydrogen to escape?

(1) 1/4

(2) 1/8

(3) 1/2

(4) 3/8

Answer 1

By Graham's law of Diffusion,

$\frac{n1}{n2} = \sqrt{ \frac{m2}{m1} } \\ \\ Here, \: let \: n1 \: and \: n2 \: be \: the \: number \: \\of \: moles \: of \: H2 \: and \: O2 \: that\: moved \: out \:\\ respectively. \\ \\ So, \: m1 = 2g \: and \: m2 = 32g \\ \\ Plugging \: the \: values, \: we \: get \\ \\ \frac{n1}{n2} = \sqrt{ \frac{32}{2} } = \sqrt{ \frac{16}{1} } \\ \\ = > \frac{n1}{n2} = \frac{4}{1} \\ \\ \\ but \: 0.5 \: of \: total \: moles \: of \: hydrogen \: moved \: out \\ \\ \frac{0.5}{n2} = 4 \\ \\ n2 = \frac{0.5}{4} = \frac{1}{8} (ans)$


*Assume that the total number of moles of each H and O2 is 1mole. Then only you can put n1 as 0.5

hope you understood!!

Answer 2

Answer:

Option B is correct answer