If $4 \ g$ of oxygen diffuse through a very narrow hole,how much hydrogen would have diffused under identical conditions? (in $g$)

$A$ closed vessel contains an equal number of molecules of $N_2$ and $O_2$ at a pressure of $650 \ mm$. If $N_2$ is completely removed,what will be the pressure in the vessel?

The ratio of rates of diffusion of oxygen and an unknown gas is $1:4$. The unknown gas is

$3.2 \ g$ of oxygen is diffused in $10 \ min$. Under similar conditions,$2.8 \ g$ of nitrogen will diffuse in .............. $min$.

At $T \ K$ and pressure $P$,the diffusion rate of an ideal gas is $120 \ mL \ min^{-1}$. What is the time taken (in sec.) for $3000 \ mL$ of this gas for diffusion at same temperature and pressure?

$A$ mixture of $0.5 \text{ mol}$ $N_2$ gas, $1.0 \text{ mol}$ $O_2$ gas and $1.5 \text{ mol}$ $H_2$ gas exerts a total pressure of $18 \text{ bar}$. Find the partial pressure of $O_2(g)$. (in $\text{ bar}$)