Mixing of two different ideal gases under isothermal reversible conditions will lead to:

When the temperature is raised,the viscosity of liquid decreases,this is because

$CH_4$ diffuses two times faster than a gas $X$. The number of molecules present in $32 \ g$ of gas $X$ is ($N$ is Avogadro number).

Two flasks $I$ and $II$ shown below are connected by a valve of negligible volume. When the valve is opened,the final pressure of the system in bar is $x \times 10^{-2}$. The value of $x$ is $.....$ . (Integer answer) [Assume-Ideal gas; $1 \, bar = 10^{5} \, Pa$; Molar mass of $N_{2} = 28.0 \, g \, mol^{-1}$; $R = 8.31 \, J \, mol^{-1} \, K^{-1}$]

$A$ $4 : 1$ molar mixture of $He$ and $CH_4$ is kept in a vessel at $20 \ bar$ pressure. Due to a hole in the vessel,the gas mixture leaks out. What is the composition of the mixture effusing out initially?

At $STP$,$0.48 \, g$ of $O_2$ gas diffuses through a porous membrane in $1200 \, s$. What volume (in $mL$) of $CO_2$ gas will diffuse under the same conditions and in the same time?