What volume does a gas occupy at $STP$?

What is the $SI$ unit of viscosity?

$X \ mL$ of $H_2$ gas effuse 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

$A$ neon-dioxygen mixture contains $70.6 \ g$ dioxygen and $167.5 \ g$ neon. If the total pressure of the mixture of gases in the cylinder is $25 \ bar$,what are the partial pressures of dioxygen and neon in the mixture?

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).

The rate of diffusion of a gas (molar mass = $128$) compared to oxygen is: