Question

A mixture of SO2 and He gases in 4:1 molar proportions is allowed to effuse through a small orifice. The ratio of number of moles of SO2 and He in the initially effused gas mixture will be​

Answer 1

As rate of effusion is inversely proportional to the square root of molar concentration. We can calculate it as R1/R2=√m2/m1

Answer 2

The ratio of number of moles of SO2 and He in the initially effused gas mixture will be 1 : 1

• According to Graham's Law of Diffusion : The rate of effusion or diffusion of a gas is inversely proportional to  the Molecular mass of the gas molecule.
• This implies that ratio of rates of diffusion or effusion of two gases is inversely proportional to the ratio of the molecular masses of two gases.
• Rate of effusion of SO2 be R1,  Rate of effusion of  He be R2
• We know Molecular mass of  SO2 is 32+2*16 = 64 be it M1
• Molecular mass of He is 4 be it M2

Now, the law implies  R1/R2 =n1/n2($\\\sqrt{M2}$/$\sqrt{M1}$)

From given data R1/R2 = 4/1 ($\sqrt{4/64}$) = 4 (1/4) = 1/1

Therefore, A mixture of SO2 and He gases in 4:1 molar proportions is allowed to effuse through a small orifice. The ratio of number of moles of SO2 and He in the initially effused gas mixture will be​ 1 :1