Final answer:
Electrostatic interactions are strongest for an ionic compound, so NaCl would have the highest boiling point. The boiling points of other compounds can be predicted by considering their polarity, ability to form hydrogen bonds, and molar mass. By comparing these factors, we can determine which gas would act most like an ideal gas under similar conditions.
Step-by-step explanation:
Electrostatic interactions are strongest for an ionic compound, so we expect NaCl to have the highest boiling point. To predict the relative boiling points of the other compounds, we must consider their polarity (for dipole-dipole interactions), their ability to form hydrogen bonds, and their molar mass (for London dispersion forces).
Helium is nonpolar and by far the lightest, so it should have the lowest boiling point. Argon and N₂O have very similar molar masses (40 and 44 g/mol, respectively), but N₂O is polar while Ar is not. Consequently, N₂O should have a higher boiling point.
A C60 molecule is nonpolar, but its molar mass is 720 g/mol, much greater than that of Ar or N₂O. Because the boiling points of nonpolar substances increase rapidly with molecular mass, C60 should boil at a higher temperature than the other nonionic substances. The predicted order is thus as follows, with actual boiling points in parentheses: He (-269°C) < Ar (-185.7°C) < N₂O (-88.5°C) < C60 (>280°C) < NaCl (1465°C).