Question

Ch4 takes 36 minutes to effuse from a container. How long will the gas take to effuse from the same container under the same conditions?

Answer 1

effusion of diffusion of gas is inversely proportional to square root of their density.
and we know, density is directly proportional to its molar mass. so, rate of effusion is inversely proportional to square root of its molar mass.

you didn't mention of which gas , we have to find effusion rate. so, I just assume gas X of molar mass X g/mol

then, $r\propto\frac{1}{\sqrt{M}}$

or, $\frac{dV}{dt}\propto\frac{1}{\sqrt{M}}$

e.g., time taken of effusion is directly proportional to square root of its molar mass

so, 36/t = √16/X

t = 9X/4 minutes .