Which of the following relations is correct regarding rate of...

According to Graham's law of diffusion, under identical conditions of temperature and pressure, the rate of diffusion of a gas is inversely proportional to the square root of its density or molecular mass.

$r \propto \dfrac{1}{\sqrt{M}}$

where $r$ is the rate of diffusion and $M$ is the molecular mass of the gas.

Therefore, the rate of diffusion is inversely proportional to the square root of its molecular mass.

Answer: inversely proportional to the square root of its molecular mass