A football bladder contains equimolar proportions of H₂ and O₂. The composition by mass of the mixture effusing out of punctured football is in the ratio (H₂ : O₂)

• According to the Graham's Law of Effusion, the rate of effusion is inversely proportional to the square-root of the molar mass.
• Rate α $\frac{1}{\sqrt{\mathrm{Molar} \mathrm{mass}}}$​ ....(1)
• Rate = $\frac{\mathrm{W}}{\mathrm{t}}$ ....(2)
• By equating equation (1) & (2), we get $\frac{{\mathrm{W}}_1}{{\mathrm{W}}_2}$​=$\sqrt{\frac{{\mathrm{M}}_2}{{\mathrm{M}}_1}}$​​....(3)
• Where, W₁= mass of H₂​

                      W₂= mass of O₂​

                      M₁= Molar mass of H_2​

                      M₂= Molar mass of O₂​

• The molar mass of H₂​ and O₂​ are 2 & 32 g/mole respectively
• $\frac{{\mathrm{W}}_1}{{\mathrm{W}}_2}$​=$\sqrt{\frac{32}{2}}$​​=4
• Answer is 4:1.