Question

$X\text{ml}$ of $H_2$ gas effused through a hole in a container in 5 seconds. The time taken for the effusion of the same volume of the gas specified below under identical conditions is:

• A. 10 seconds : $He$
• B. 20 seconds : $O_2$
• C. 25 seconds : $CO$
• D. 35 seconds : $C{O}_2$

Answer 1

The correct option is B 20 seconds : $O_2$

According to Graham's law of diffusion, rate is inversely propotional to sqaure root of molecular weight.
$\therefore$ (a) is incorrect $\frac{r_{H_2}}{r_{He}}=\sqrt{\frac{4}{2}}=\sqrt{2}$
$\frac{r_{H_2}}{r_{O_2}}=\sqrt{\frac{32}{2}}=4$
(b) is correct
$\frac{r_{H_2}}{r_{CO}}=\sqrt{\frac{28}{2}}=\sqrt{14}$
(c) is incorrect
$\frac{r_{H_2}}{r_{C{O}_2}}=\sqrt{\frac{44}{2}}=\sqrt{\frac{22}{1}}$
(d) is incorrect