# The time for a certain volume of a gas A to diffuse through a small hole is 2 minute. If it takes 5.65 minute for oxygen to diffuse under simililar conditions. Find the molecular weight of A.

$(a)\;1\qquad(b)\;2\qquad(c)\;3\qquad(d)\;4$

$\large\frac{r_A}{r_{O_2}} = \sqrt{\large\frac{MO_2}{MA}}$
$\;\;\;\;\;\;\;=\large\frac{t_{O_2}}{t_A}$
$\sqrt{\large\frac{32}{M_A}}= \large\frac{5.65}{2}$
$\therefore M_A = 4$