Question

The molecular weight of a gas which diffuses through a porous plug at 1/6th of the speed of hydrogen under identical conditions is:

• A. $12$
• B. $72$
• C. $64$
• D. $36$

Answer 1

The correct option is B $72$

$\frac{D_x}{D_{H_2}}=\frac{\sqrt{M_{H_2}}}{\sqrt{M_x}}⟹\frac{1}{6}=\frac{\sqrt{2}}{\sqrt{M_x}}⟹M_x=72g{mol}^{-1}$