JAMB Chemistry 2019 Paper

Concept:Graham's law of diffusion states that the rate of diffusion of a gas is inversely proportional to the square root of its molar mass.Explanation:Let the rate of hydrogen be $R_{\mathrm{H}_2}$ and the rate of oxygen be $R_{\mathrm{O}_2}$.According to Graham's law:$$\frac{R_{\mathrm{H}_2}}{R_{\mathrm{O}_2}} = \sqrt{\frac{M_{\mathrm{O}_2}}{M_{\mathrm{H}_2}}}$$Molar mass of oxygen, $M_{\mathrm{O}_2} = 32$Molar mass of hydrogen, $M_{\mathrm{H}_2} = 2$Substitute the values:$$\frac{R_{\mathrm{H}_2}}{R_{\mathrm{O}_2}} = \sqrt{\frac{32}{2}} = \sqrt{16} = 4$$Therefore, $R_{\mathrm{H}_2} = 4 \times R_{\mathrm{O}_2}$.Answer:Hydrogen diffuses four times as fast as oxygen.Correct option: C.