Question

If the four tubes of a car are filled to the same pressure with $N_2,O_2,H_2$ and $C{O}_2$ separately, then which one will be filled first?

• A. $N_2$
• B. $O_2$
• C. $H_2$
• D. $C{O}_2$

Answer 1

The correct option is C $H_2$

Under identical conditiosn of T and p, the rates of effusion for gaseous substances are inversely proportional to the square roots of their molar masses:

$r\propto \sqrt{\frac{1}{\text{Molecular mass}}}$

Lower the molecular mass , faster it wil effuse out and will be filled first. Thus , $H_2$ gas with the lowest molecular mass is filled first.