Alcohols have much higher boiling points than alkanes of similar molar mass because

  • A. their molecules are hydrogen bonded to one another
  • B. they are ionic compounds
  • C. their covalent bonds are stronger
  • D. they have larger molecules

Explanation

The hydroxyl group allows hydrogen bonding between molecules, and a great deal of extra energy is needed to break those bonds before the liquid can boil, so ethanol boils at 78 degrees Celsius while propane, of similar mass, boils at minus 42. The same hydrogen bonding makes the shorter alcohols completely miscible with water. Boiling point does not depend on the strength of bonds inside the molecule.

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