If methane and helium are allowed to diffuse out of a container under identical conditions of temperature and pressure, the ratio of rate of diffusion of methane to helium is:
0.5
RCH4= Rate of diffusion of Methane
RHe = Rate of diffusion of Helium
From Graham's law of diffusion,
RCH4RHe=√MHeMCH4=√416=0.5
The ratio is Rate of diffusion of MethaneRate of diffusion of Helium=1:2=0.5