The rate of diffusion of a gas is 

a) 
Directly proportional to its density 
b) 
Directly proportional to its molecular weight 
c) 
Directly proportional to the square root of its molecular weight 
d) 
Inversely proportional to the square root of its molecular weight 
The rate of diffusion of a gas is 

a) 
Directly proportional to its density 
b) 
Directly proportional to its molecular weight 
c) 
Directly proportional to the square root of its molecular weight 
d) 
Inversely proportional to the square root of its molecular weight 
(d) According to Graham’s law of diffusion, the rate at which a gas diffuses is inversely proportional to the density of the gas. The movement of gas molecules from one place to the other along the concentration gradient is called diffusion. When they are allowed to escape through a tiny hole under pressure, this phenomenon is called effusion Rate of diffusion of gas Since the vapour density is (molar mass) 