Chapter 14 Aldehydes, Ketones, and Chiral Molecules 14.2 Physical Properties of Aldehydes and Ketones

Polar Carbonyl Group The polar carbonyl group provides dipole–dipole interactions does not have H on the oxygen atom cannot form hydrogen bonds

Boiling Points Aldehydes and ketones have polar carbonyl groups (C═O) attractions between polar groups higher boiling points than alkanes and ethers of similar mass lower boiling points than alcohols of similar mass

Comparison of Boiling Points

Comparison of Physical Properties

Learning Check Select the compound in each pair that would have the higher boiling point. Explain. A. CH3—CH2—CH3 or CH3—CH2—OH B. or C. CH3—CH2—OH or CH3—O—CH3

Solution Select the compound in each pair that would have the higher boiling point. Explain. A. CH3—CH2—OH An alcohol forms hydrogen bonds. B. There are dipole–dipole attractions between the carbonyl groups C. CH3—CH2—OH An alcohol forms hydrogen bonds, but an ether does not.

Solubility in Water Aldehydes and ketones are soluble in water have electronegative O atoms in their carbonyl groups that form hydrogen bonds with water

Learning Check Indicate if each of the following is or is not soluble in water: A. CH3—CH2—CH3 B. CH3—CH2—OH C. D.

Solution Indicate if each of the following is or is not soluble in water: A. CH3—CH2—CH3 B. CH3—CH2—OH C. D. not soluble in water soluble in water soluble in water soluble in water