The ratio of vapour density of two gases is 4:9 at the same temperature. Compare the r.m.s velocities of their molecules.
2:3
3:2
4:9
8:18
The ratio of the r.m.s velocities is given as:
Under the same conditions, the rates of diffusion of two gases are in the ratio 1 : 4. The ratio of their vapour densities is ___.