How can comparing the rates of effusion of gases X and Y allow the molar mass of Y to be calculated? Write an equation stating the relationship between the ratio of the X and Y rates of effusion and their molar masses, MX and MY.

Explanation:

Gases are:

Gas 1  = X

Gas 2  = Y

To calculate the rates of effusion we apply the Graham's Law of Diffusion of Gases.

The law relates the rate of diffusion or effusion of a gas to the type of molecule in the gas.

It is expressed as "the rate of diffusion or effusion of a gas is inversely proportional to the square root of its molecular mass or density at constant temperature and pressure".

A gas with low molecular mass can diffuse or effuse more rapidly than one with high molecular mass under similar conditions.

By this, we can express a mathematical relationship to solve for the molecular masses of the gases.

r is the rate of diffusion

m is the molecular mass

the answer is definitely c.