Question

A gas which diffuses 4 times slowly than $H_2$ gas is:

• A. $H_{2}S$
• B. $O_2$
• C. ${CH}_4$
• D. ${SO}_2$

Answer 1

Answer: (B)

$O_2$

Diffusion coefficient, $D\propto \frac{1}{\sqrt{M}}$

Now, $M_{H_2}=2gmo{l}^{-1}$, $M_2=?$

$\therefore$ As the gas having molecular weight $M_2$ diffuses four times slowly than $H_2$.

$D_2=\frac{D_{H_2}}{4}$

$\therefore \frac{D_{H_2}}{4}\frac{D_2}{D_{H_2}}=\sqrt{\frac{M_{H_2}}{M_2}}⟹\frac{1}{4}=\sqrt{\frac{2}{M_2}}⟹M_2=32g{mol}^{-1}$

$\therefore$ The gas is $O_2$.