Answer:
Diffusion of a gas is best described using Grahams law of diffusion. It states that the rate of diffusion of gas is inversely proportional to the molecular weight of gas.
diffusion generally occurs from a region of high concentration to a region of low concentration. Diffusion occurs in liquids , gases .
Generally we sense the smell of chlorine when it is leaked , Here chlorine gas is initially in cylinder at a higher concentration and a higher pressure . Now it is diffused in to surroundings where it have lower pressure and lower concentration.