Which of the following will have the lowest boiling point?

• A. CH₃–O–CH₃
• B. KI
• C. C₆H₅OH
• D. C₆H₁₄
• E. C₆₀

Answer: (D)

Verified step by step guidance

1. Identify the substances given: CH\_3–O–CH\_3 (dimethyl ether), KI (potassium iodide), C\_6H\_5OH (phenol), C\_6H\_14 (hexane), and C\_60 (buckminsterfullerene).
2. Recall that boiling point depends largely on the type and strength of intermolecular forces present in each substance. Stronger intermolecular forces lead to higher boiling points.
3. Classify the intermolecular forces for each compound: - CH\_3–O–CH\_3 has dipole-dipole interactions and London dispersion forces. - KI is an ionic compound with strong ionic bonds. - C\_6H\_5OH has hydrogen bonding, dipole-dipole, and dispersion forces. - C\_6H\_14 is a nonpolar molecule with only London dispersion forces. - C\_60 is a large nonpolar molecule with significant London dispersion forces due to its size.
4. Compare the strength of these forces: Ionic bonds (KI) are the strongest, followed by hydrogen bonding (C\_6H\_5OH), then dipole-dipole (CH\_3–O–CH\_3), and finally London dispersion forces (C\_6H\_14 and C\_60). Larger molecules generally have stronger dispersion forces.
5. Since C\_6H\_14 is a small nonpolar molecule with only weak London dispersion forces, it will have the lowest boiling point among the options.