Question

If some moles of O2 diffuse in 18 sec and
same moles of other gas diffuse in 45 sec
then what is the molecular weight of the
unknown gas?
- 452
182
182
452
(3
452 x 32 (4) 18² x 32
de​

Answer 1

Answer:-

200g

Explanation:-

Given:-

Some moles of oxygen diffuses in,

• $t_1 = 18 sec$

same moles of other gas diffuses in,

• $t_2 = 45 sec$

To Find:-

Molecular wt. of the unknown gas

Solution:-

let, the unknown be X

w.k.t,

$\boxed{\bold{r = \dfrac{v}{t}}}$

$\boxed{\bold{r = \dfrac{P}{\sqrt{m}}}}$

P α n

Therefore,

$\boxed{\bold{r = \dfrac{n}{\sqrt{m}}}}$

$\dfrac{v}{18} = \dfrac{n}{\sqrt{M_{O_2}}}$

$\dfrac{v}{18} = \dfrac{n}{\sqrt{32}}----(1)$

$\dfrac{v}{45} = \dfrac{n}{\sqrt{M_{X}}}-----(2)$

Eq (1)/(2)

$\dfrac{v}{18} \times \dfrac{45}{v}= \sqrt{\dfrac{M_X}{32}}$

$\dfrac{5}{2}= \sqrt{\dfrac{M_X}{32}}$

${(\dfrac{5}{2})}^{2}= \dfrac{M_X}{32}$

$\dfrac{25}{4}= \dfrac{M_X}{32}$

$M_X = 200g$