120 likes | 154 Views
Chapter 16 Carboxylic Acids and Esters. 16.2 Properties of Carboxylic Acids. Polarity of Carboxylic Acids. Carboxylic acids are strongly polar have two polar groups: hydroxyl ( − OH) and carbonyl (C═O). Boiling Points of Carboxylic Acids. The boiling points (bp) of carboxylic acids
E N D
Chapter 16 Carboxylic Acids and Esters 16.2Properties of Carboxylic Acids
Polarity of Carboxylic Acids Carboxylic acids • are strongly polar • have two polar groups: hydroxyl (−OH) and carbonyl (C═O)
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 dimersin which hydrogen bonds form between two polar carboxyl groups
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
Acidity of Carboxylic Acids Carboxylic acids • are weak acids • ionize in water to produce carboxylate ions and hydronium ions
Acid Dissociation Constants Carboxylic acids • have small Ka values • exist mostly as molecules and a few ions in aqueous solutions
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) • areused as preservatives and flavor enhancers
Learning Check Write the equation for the reaction of propanoic acid with: A. water B. KOH
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