The rate of diffusion of a gas is

$A$ mixture of $N_2$ and $Ar$ gases in a cylinder contains $7 \ g$ of $N_2$ and $8 \ g$ of $Ar$. If the total pressure of the mixture of gases in the cylinder is $27 \ bar$,the partial pressure of $N_2$ is $......... \ bar$.
[Use atomic masses (in $g \ mol^{-1}$) : $N=14, Ar=40$]

The density of a gas at $STP$ is $2.86 \, g \, L^{-1}$. Which gas is it?

On what factor does the magnitude of surface tension depend?

Calculate the partial pressure exerted by dioxygen from a mixture of $32 \ g$ $O_2$,$80 \ g$ $Ar$ (molar mass $40 \ g/mol$) and $4 \ g$ dihydrogen $(P_{\text{total}} = 10 \ bar)$. (in $bar$)

How will the viscosity of a liquid be affected by an increase in temperature?