The volume of $1$ mole of any pure gas at standard temperature and pressure $(STP)$ is always equal to (in $m^3$)

$50 \ mL$ of hydrogen diffuses out through a small hole from a vessel in $20 \ min$. The time needed for $40 \ mL$ of oxygen to diffuse out is ............. $min$.

$A$ mixture of one mole each of $H_2$,$He$ and $O_2$ are enclosed in a cylinder of volume $V$ at temperature $T$. If the partial pressure of $H_2$ is $2 \ atm$,the total pressure of the gases in the cylinder is $....... \ atm$

If a saturated vapor is slowly compressed (at constant temperature) to half of its initial volume,what happens to the vapor pressure?

At $T \ K$,equal weights of $H_2, D_2$,and $T_2$ are present in a closed vessel. The pressure exerted by this gaseous mixture is $P \ atm$. The ratio of partial pressures of $T_2, D_2$,and $H_2$ is approximately. ($H, D$ and $T$ are isotopes of hydrogen).

$A$ container contains $5 \ mol$ of $A$ and $10 \ mol$ of $B$. The total pressure of the container is $18 \ atm$. What are the partial pressures $P_A$ and $P_B$ respectively?