Final answer:
Among Br₂, NaBr, HBr, and BrF, the substance with the highest boiling point is NaBr because it is an ionic compound with strong electrostatic attractions between ions.
Step-by-step explanation:
The substance with the highest boiling point among Br₂, NaBr, HBr, and BrF is NaBr. To determine which substance has the highest boiling point, we need to consider the type of bonding and intermolecular forces present in each substance. Bromine (Br₂) is a diatomic molecule held together by London dispersion forces, making its boiling point higher than that of BrF, which is a polar covalent molecule but with less molar mass and thus weaker dispersion forces.
Hydrogen bromide (HBr) also exhibits dipole-dipole interactions due to its polar covalent bond, but does not have sufficient molar mass to raise its boiling point higher than that of NaBr. Sodium bromide (NaBr) is an ionic compound, and ionic bonds result in a very high boiling point due to the strong electrostatic attractions between ions that require considerable energy to overcome. Thus, NaBr will have the highest boiling point among the given substances.