Which of the following gases is not easily soluble in water?

$A$ mixture of equal masses of two gases with molecular weights $4$ and $40$ has a total pressure of $1.1 \, atm$. The partial pressure of the lighter gas in the mixture is ............ $atm$.

$A$ closed vessel contains an equal number of molecules of $N_2$ and $O_2$ at a pressure of $650 \ mm$. If $N_2$ is completely removed,what will be the pressure in the vessel?

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 $bar$)

Four rubber tubes are filled with $H_2, O_2, N_2$,and $He$ respectively. Which of these tubes will deflate first?

What will be the pressure at $0\,^oC$ in Kolkata,Chennai,and Mumbai (in $,bar$)?