Question

$Xml$ of $H_2$ gas effuses through a hole in a container in 5 seconds. The time taken for the effusion of the same volume of the gas specified below under identical conditions is

• A. $10sec,He$
• B. $20sec,O_2$
• C. $25sec,CO$
• D. $55sec,C{O}_2$

Answer 1

The correct option is B $20sec,O_2$

From equation for diffusion
$\frac{T_1}{T_2}=\sqrt{\frac{M_1}{M_2}}\Rightarrow T_1=T_2\sqrt{\frac{M_1}{M_2}}\Rightarrow T_1=5\sqrt{\frac{M_1}{2}}$

a) For $He$, $T_1=5\sqrt{\frac{4}{2}}\ne 10$
b) For $O_2$, $T_1=5\sqrt{\frac{32}{2}}=20$
c) For $CO$, $T_1=5\sqrt{\frac{28}{2}}\ne 25$
d) For $C{O}_2$, $T_1=5\sqrt{\frac{44}{2}}\ne 55$