Question

A dipole moment tends to stabilize the liquid state of the compound as molecules align to form attractive molecular interactions. A liquid state that is more stable, that is one that is held together by stronger dipole forces, will have a higher boiling point since it takes more energy to break these intermolecular forces. Rank the following compounds in order of decreasing boiling point: sodium chloride (NaCl), carbon tetrafluoride (CF₄), and iodomethane (CH₃I)

A) NaCl > CH₃I > CF₄
B) CH₃I > NaCl > CF₄
C) CF₄ > CH₃I > NaCl
D) NaCl > CF₄ > CH₃I

Answer 1

The boiling point of a liquid is influenced by the strength of the intermolecular forces. Sodium chloride (NaCl) has the highest boiling point due to its strong electrostatic interactions. Carbon tetrafluoride (CF₄) has the lowest boiling point as it only experiences weak dispersion forces. Iodomethane (CH₃I) has a higher boiling point than CF₄ but lower than NaCl due to dipole-dipole interactions.

Step-by-step explanation:

The boiling point of a liquid is influenced by the strength of the intermolecular forces. The stronger the intermolecular forces, the higher the boiling point. In this case, we can rank the compounds in order of decreasing boiling point by considering the type of intermolecular forces present. Sodium chloride (NaCl) is an ionic compound and has the strongest electrostatic interactions, so it will have the highest boiling point. Carbon tetrafluoride (CF₄) is a nonpolar molecule, so it only experiences weak dispersion forces and will have the lowest boiling point. Iodomethane (CH₃I) is a polar molecule and experiences dipole-dipole interactions, so it will have a higher boiling point than CF₄ but lower than NaCl. Therefore, the correct ranking is NaCl > CH₃I > CF₄.