What is the $SI$ unit of rate of diffusion for a gas?

$300 \ mL$ of a gas '$x$' of molar mass $32 \ g \ mol^{-1}$ is effused in $25 \ s$. What volume of methane would effuse in the same time (in $mL$)?

$A$ mixture of equal masses of ethane $(C_2H_6)$ and hydrogen $(H_2)$ is filled in an empty container at $25\,^oC$. What is the fraction of the total pressure exerted by hydrogen?

Show the relationship between different units of pressure.

What is the difference between a barometer and a manometer?

At $T(K)$,a gaseous mixture containing $H_2, He$ and $O_2$ exerted a pressure of $1 \ bar$. The weight percentage of $H_2$ and $He$ is $20$ and $16$ respectively. The partial pressure (in bar) of $H_2, He$ and $O_2$ is respectively