# under similar conditions which of the following gas will diffuse 4 times as quickly as O2 ? (a)Helium , (b)H2 , (c)N2 , (d)Cl2 . and how?​

According to Graham's Law, diffusion of a gas is inversely proportional to the square root of the molar mass of the gas:
$\frac{{\mathrm{Rate}}_{\mathrm{He}}}{{\mathrm{Rate}}_{\mathrm{O}2}}=\sqrt{\frac{{\mathrm{M}}_{{\mathrm{O}}_{2}}}{{\mathrm{M}}_{\mathrm{He}}}}=\sqrt{\frac{32}{4}}=2\sqrt{2}\phantom{\rule{0ex}{0ex}}$
$\frac{{\mathrm{Rate}}_{{\mathrm{H}}_{2}}}{{\mathrm{Rate}}_{{\mathrm{O}}_{2}}}=\sqrt{\frac{{\mathrm{M}}_{{\mathrm{O}}_{2}}}{{\mathrm{M}}_{{\mathrm{H}}_{2}}}}=\sqrt{\frac{32}{2}}=4\phantom{\rule{0ex}{0ex}}$
$\frac{{\mathrm{Rate}}_{{\mathrm{N}}_{2}}}{{\mathrm{Rate}}_{{\mathrm{O}}_{2}}}=\sqrt{\frac{{\mathrm{M}}_{{\mathrm{O}}_{2}}}{{\mathrm{M}}_{{\mathrm{N}}_{2}}}}=\sqrt{\frac{32}{28}}\phantom{\rule{0ex}{0ex}}$
$\frac{{\mathrm{Rate}}_{{\mathrm{Cl}}_{2}}}{{\mathrm{Rate}}_{{\mathrm{O}}_{2}}}=\sqrt{\frac{{\mathrm{M}}_{{\mathrm{O}}_{2}}}{{\mathrm{M}}_{{\mathrm{Cl}}_{2}}}}=\sqrt{\frac{32}{34}}\phantom{\rule{0ex}{0ex}}$
Rate of diffusion of hydrogen is 4 times the rate of diffusion of oxygen.