Question

One litre of methane takes 20 minutes to diffuse out of a vessel. How long will it take to diffuse one litre of $S{O}_2$ through the vessel under the same conditions of temperature and pressure?

• A. 40 $min$
• B. 24 $min$
• C. 20 $min$
• D. 10 $min$

Answer 1

The correct option is A 40 $min$

Graham's law states that "at constant pressure and temperature the rate of diffusion or effusion of a gas is inversly proportional to the square root of its density".

$r_1/r_2=\sqrt{M_2/M_1}$

$r_{C{H}_4}/r_{S{O}_2}=\frac{1000/20}{1000/t}$

$\frac{1000/20}{1000/t}=\sqrt{64/16}$

$t=40$ min