Which one is an example of a solid solution?

$5.5 \text{ mg}$ of nitrogen gas dissolves in $180 \text{ g}$ of water at $273 \text{ K}$ and $1 \text{ atm}$ pressure due to nitrogen gas. The mole fraction of nitrogen in $180 \text{ g}$ of water at $5 \text{ atm}$ nitrogen pressure is approximately:

The Henry's law constant for the solubility of $N_2$ gas in water at $25 \, ^oC$ is $1 \times 10^5 \, atm$. The mole fraction of $N_2$ in air is $0.8$. Calculate the number of moles of $N_2$ from air that will dissolve in $10 \, moles$ of $H_2O$ at $25 \, ^oC$ and at a total pressure of $5 \, atm$.

$1 \ g$ of silver gets distributed between $10 \ cm^{3}$ of molten zinc and $100 \ cm^{3}$ of molten lead at $800^{\circ} C$. The percentage of silver still left in the lead layer is approximately

Why do gases always tend to be less soluble in liquids as the temperature is raised?

Rank the following solvents in decreasing order of their ability to dissolve the given solute (naphthalene).