1. Chapter 16 Carboxylic Acids and Esters
16.2 Properties of Carboxylic Acids

2. Polarity of Carboxylic Acids
are strongly polar
have two polar groups:
hydroxyl (−OH) and carbonyl (C═O)

3. Boiling Points of Carboxylic Acids
The boiling points (bp) of carboxylic acids
are higher than those of alcohols, ketones, and aldehydes of similar mass
are high because they form dimers in which hydrogen bonds form between two polar carboxyl groups

4. Comparison of Boiling Points

5. Solubility in Water Carboxylic acids
form hydrogen bonds with many water molecules
with 1 to 4 carbon atoms are very soluble in water
Water molecules

6. Boiling Points and Solubility

7. Acidity of Carboxylic Acids
are weak acids
ionize in water to produce carboxylate ions and hydronium ions

8. Acid Dissociation Constants
Carboxylic acids
have small Ka values
exist mostly as molecules and a few ions in aqueous solutions

9. Neutralization of Carboxylic Acids
Carboxylic acid salts
are a product of the neutralization of a carboxylic acid with a strong base:
CH3—COOH + NaOH CH3—COO– Na+ + H2O
Acetic acid Sodium acetate
(carboxylic acid salt)
are used as preservatives and flavor enhancers

10. Learning Check
Write the equation for the reaction of propanoic acid with:
A. water
B. KOH

11. Solution Write the equation for the reaction of propanoic acid with:
A. water
CH3—CH2—COOH + H2O CH3—CH2—COO– + H3O+
B. KOH
CH3—CH2—COOH + KOH CH3—CH2—COO– K+ + H2O