Certain volume of oxygen gas diffuses through a porous pot in 20 seconds. Same volume of another gas (X) diffuses in Y seconds as that of oxygen, then (X) and Y respectively are

$$\begin{gathered} \frac{{\left(\frac{\mathrm{Volume} \mathrm{diffused}}{\mathrm{time}}\right)}_{\mathrm{oxygen} \mathrm{gas}}}{{\left(\frac{\mathrm{Volume} \mathrm{diffused}}{\mathrm{time}}\right)}_{\mathrm{B}}}=\sqrt{\frac{{\mathrm{M}}_{\mathrm{B}}}{{\mathrm{M}}_{\mathrm{oxygen} \mathrm{gas}}}} \\ \mathrm{Molar} \mathrm{mass} \mathrm{of} \mathrm{oxygen} \mathrm{gas} \mathrm{is} 32 \mathrm{g}/\mathrm{mol}. \mathrm{Same} \mathrm{volume} \left(\mathrm{V}\right) \\ \frac{\mathrm{Y} \sec }{20}=\sqrt{\frac{\mathrm{X}}{32}} \\ \frac{{\mathrm{Y}}^2}{20\times 20}=\frac{\mathrm{X}}{32} \\ \frac{5\times 5}{20\times 20}=\frac{2}{32} \\ \frac{1}{16}=\frac{1}{16} \\ \mathrm{X}=\mathrm{He} \mathrm{gas} \mathrm{and} \mathrm{Y} \sec =5 \sec \end{gathered}$$