Which intermolecular forces contribute to the dissolution of nacl in hexane?

Hexane is nonpolar, so you would not see dipole-dipole, hydrogen-bonding, or ion-dipole interactions involving it. London dispersion forces always exist however, and the ion-ion force between Na+ and Cl- will still exist since it's not dependent on the environment. So 2 and 5 would be check-marked.

The air is going to come out because of the low pressure.

The answer should be vaporization