Which of the following gases diffuses the fastest? o 2 , ch 4 , co 2 , cl 2 o 2 ch 4 co 2 cl 2

Methane (CH₄).

Explanation:

Thomas Graham found that, at a constant  temperature and pressure the rates of effusion of various gases are inversely proportional to  the square root of their masses.

∨ ∝ 1/√M

where ν is the rate of effusion and M is the atomic  or molecular weight of the gas particles.

The lighter gases move more quickly than heavier ones at the same temperature.

So, Methane has smallest molecular mass and diffuses the fastest.