$A$ gas diffuses $1/3$ times as fast as hydrogen. Its molecular weight is

$A$ sample of $O_2$ gas is collected over water at $23\,^oC$ and a barometric pressure of $751\,mm\,Hg$. What is the partial pressure of the $O_2$ gas in this sample? (Vapor pressure of water at $23\,^oC$ is $21\,mm\,Hg$)

At the same temperature and pressure,the rate of diffusion of gas $X$ is $3 \sqrt{3}$ times that of a gaseous hydrocarbon of molar mass $54 \ g \ mol^{-1}$. The molar mass of $X$ in $g \ mol^{-1}$ is

The rate of diffusion of $SO_2$,$CO_2$,$PCl_3$ and $SO_3$ are in the following order:

At a constant temperature and pressure,the ratio of the densities of two gases is $1 : 16$. The ratio of their rates of diffusion will be ........

The rate of diffusion of a gas is inversely proportional to