Question 1

The compound shown is a cyclic amide (lactam). When it is heated with aqueous HCl, what are the major organic products of this reaction?

Accepted Answer

5-aminopentanoic acid (as its hydrochloride salt)

Question 2

Which type of reaction is illustrated by the hydrolysis of the cyclic amide (lactam) in the presence of aqueous HCl and heat?

Accepted Answer

Nucleophilic acyl substitution (acid-catalyzed hydrolysis)

Question 3

What is the balanced chemical equation (in molecular form) for the acid-catalyzed hydrolysis of the given lactam (caprolactam) with water and HCl?

Accepted Answer

$$\mathrm{C_5H_9NO} + \mathrm{H_2O} + \mathrm{HCl} \rightarrow \mathrm{C_5H_{11}NO_2$ \cdot HCl}$$

Question 4

During the acid-catalyzed hydrolysis of a lactam, which functional group is formed in the organic product?

Accepted Answer

A carboxylic acid and an amine

Question 5

Which of the following best describes the role of HCl in the hydrolysis of the lactam?

Accepted Answer

It acts as a catalyst by protonating the carbonyl oxygen, increasing electrophilicity.

Question 6

If the reaction is performed with NaOH instead of HCl, what would be the major difference in the products?

Accepted Answer

The amine would be in its free base form and the carboxylate as a sodium salt.

Question 7

Which of the following statements about the mechanism of acid-catalyzed hydrolysis of a lactam is correct?

Accepted Answer

The first step is nucleophilic attack by water on the carbonyl carbon after protonation.

Question 8

Which of the following best explains why heat ($$\Delta) is $$required for this reaction?

Accepted Answer

To increase the rate of hydrolysis by providing energy to break the amide bond.

Question 9

Which of the following is a real-world application of the acid-catalyzed hydrolysis of lactams?

Accepted Answer

Degradation of nylon polymers in acidic environments

Question 10

If the starting lactam is caprolactam (a 6-membered ring), what is the product of its acid-catalyzed hydrolysis?

Accepted Answer

6-aminocaproic acid (as its hydrochloride salt)

Hydrolysis of Lactams: Acid-Catalyzed Reaction Mechanism

Study Guide - Practice Questions