Question

What is the ratio of rates of effusion of one mole of $O_2$ and one mole of $H_2$, if both are kept at identical pressure and temprature?

• A. $1:4$
• B. $2:1$
• C. $1:8$
• D. $4:1$

Answer 1

The correct option is A $1:4$

Rate of effusion of gas $\propto \frac{1}{\sqrt{M}}$
where M is molecular mass.
To find the ratio,
$\frac{r_{O_2}}{r_{H_2}}=\sqrt{\frac{M_{H_2}}{M_{O_2}}}=\sqrt{\frac{2}{32}}=\frac{1}{4}$