Question

Density ratio of $O_2$ and $H_2$ is $16:1$. The ratio of their rate of effusion under same conditions is

• A. $4:1$
• B. $1:4$
• C. $1:2$
• D. $2:1$

Answer 1

The correct option is B $1:4$

We know,
From Graham's law of effusion of gas,
$r\propto \frac{1}{\sqrt{\rho }}$
So,
$\frac{r_{O_2}}{r_{H_2}}=\sqrt{\frac{{\rho }_{H_2}}{{\rho }_{O_2}}}=\sqrt{\frac{1}{16}}=\frac{1}{4}$