If the density of a mixture of nitrogen and oxygen gases at $400 \ K$ and $1 \ atm$ pressure is $0.920 \ g \ L^{-1}$, what is the mole fraction of nitrogen in the mixture? ($R=0.082 \ L \ atm \ mol^{-1} \ K^{-1}$; assume ideal gas behavior for oxygen and nitrogen)

In which one of the following,does the given amount of chlorine exert the least pressure in a vessel of capacity $1 \ dm^{3}$ at $273 \ K$?

$A$ $10 \ g$ mixture of hydrogen and helium is contained in a vessel of capacity $0.0125 \ m^{3}$ at $6 \ bar$ and $27^{\circ}C$. The mass of helium in the mixture is $g$. (nearest integer) Given : $R = 8.3 \ J \ K^{-1} \ mol^{-1}$ (Atomic masses of $H$ and $He$ are $1 \ u$ and $4 \ u$,respectively)

What is the relationship between viscosity and density?

Equal weights of $CH_4$ and $H_2$ are mixed in an empty container at $25 \, ^oC$. The fraction of the total pressure exerted by $H_2$ would be

$A$ mixture of $He$ and $CH_4$ in a molar ratio of $4:1$ is present in a container at a pressure of $20 \ bar$. Due to a hole in the container,the gas mixture leaks out. What will be the composition of the gas mixture effusing out initially (in $: 1$)?