The rate of diffusion of a gas is

Options

A. Directly proportional to its density
B. Directly proportional to its molecular weight
C. Directly proportional to the square root of its molecular weight
D. Inversely proportional to the square root of its molecular weight

Explanation

According to Graham's law of diffusion, the rate at which a gas diffuse is inversely proportional to the density of the gas. The movement of gas molecules from one place to the other along the concentration gradient is called diffusion. When they are allowed to escape through a tiny hole under pressure, this phenomenon is called effusion.
Rate of diffusion of gas `=("Volume of the gas diffusion")/("Time taken")`
`r prop (1)/(sqrt(d))`
`(r_(1))/(r_(2))=sqrt((d_(2))/(d_(1))`
Since the vapour density is `M//2` (molar mass)
`(r_(1))/(r_(2))=sqrt((M_(2))/(M_(1))`