Question

how do you show experimently that hydrogen diffuses faster than air​

Answer 1

Colouring the water helps. Then place a gas jar filled with hydrogen over the top of the porcelain, and leave it there whilst diffusion takes place. Hydrogen molecules diffuse into the jar faster than the air molecules diffuse out, so the pressure inside builds and the water in the glass tube is forced down.

Answer 2

It states that the diffusion rate of a gas is inversely proportional to the square root of its molar mass (molecular weight). Stated in simpler terms, lighter gases (in terms of density or molecular weight) will diffuse faster than those gases with higher densities or molecular weight.