Question

Calculate the ratio of effusion rates for helium and argon.

Answer 1

Answer : The ratio of effusion rates for helium and argon is 3.2 : 1

Solution : Given,

Molar mass of Helium = 4 g/mole

Molar mass of Argon = 40 g/mole

Rate of effusion : It is defined as the rate of effusion of a gas is inversely proportional to the square root of the molar mass of the gas.

Formula used :

$\text{Rate of effusion}=\frac{1}{\sqrt{M}}$

where, M is the molar mass.

$\frac{Rate_{He}}{Rate_{Ar}}=\sqrt{\frac{M_{Ar}}{M_{He}}}$

Now put all the given values in this expression, we get

$\frac{Rate_{He}}{Rate_{Ar}}=\sqrt{\frac{40}{4}}=\frac{3.2}{1}$

Therefore, the ratio of effusion rates for helium and argon is 3.2 : 1