Question 1

Which of the following statements best explains why primary and secondary amines have higher boiling points than tertiary amines of similar molecular weight?

Accepted Answer

Primary and secondary amines can form hydrogen bonds with themselves, while tertiary amines cannot.

Question 2

Which of the following compounds is a secondary amine?

Accepted Answer

$$\mathrm{(CH_3CH_2)_2NH}$$

Question 3

Which of the following best describes the behavior of amines in aqueous solution?

Accepted Answer

Amines act as Lewis bases and accept a proton from water, forming ammonium ions and hydroxide ions.

Question 4

Which of the following is the correct name for the compound $$\mathrm{C_6H_5NH_2}$$?

Accepted Answer

Aniline

Question 5

What is the product when a tertiary amine reacts with hydrochloric acid?

Accepted Answer

A quaternary ammonium salt

Question 6

Which of the following statements about the solubility of amines in water is correct?

Accepted Answer

All amines can form hydrogen bonds with water, increasing their solubility.

Question 7

Which of the following best explains why amine drugs are often administered as ammonium salts?

Accepted Answer

Ammonium salts are more water-soluble than neutral amines, making them easier to transport in the bloodstream.

Question 8

Which of the following is a heterocyclic amine found in DNA and anticancer drugs?

Accepted Answer

Purine

Question 9

A compound has the formula $$\mathrm{(CH_3$)_3N}. $$What is the correct classification and why?

Accepted Answer

Tertiary amine, because the nitrogen is bonded to three carbon groups and no hydrogens.

Question 10

Which of the following best describes the effect of pH on the form of an amine in the human body?

Accepted Answer

At low pH (acidic), the amine exists primarily as a charged ammonium ion.

Question 11

Which of the following is a correct statement about the basicity of aromatic versus nonaromatic amines?

Accepted Answer

Aromatic amines are weaker bases than nonaromatic amines.

Question 12

Which of the following best explains why amphetamine is absorbed in the small intestine but not in the stomach?

Accepted Answer

Amphetamine is ionized (charged) in the acidic stomach, but neutral in the more basic small intestine, allowing it to cross cell membranes.

Question 13

Which of the following is the correct conjugate acid-base pair for methylamine ($$\mathrm{CH_3NH_2}$$)?

Accepted Answer

$$\mathrm{CH_3NH_3^+}$$ / \mathrm{CH_3NH_2}$

Question 14

Which of the following is a property of quaternary ammonium salts?

Accepted Answer

They cannot react with base to form a neutral amine.

Question 15

Which of the following best describes an alkaloid?

Accepted Answer

A naturally occurring, nitrogen-containing compound isolated from a plant.

Question 16

Which of the following is the correct name for the ammonium ion formed from aniline?

Accepted Answer

Anilinium ion

Question 17

Which of the following best explains why amines are lower boiling than alcohols of similar size?

Accepted Answer

Hydrogen bonds between O-H are stronger than those between N-H.

Question 18

Which of the following is a correct statement about the water solubility of amines and their salts?

Accepted Answer

Amines are more water-soluble when they are charged (as ammonium ions).

Question 19

Which of the following is a correct example of a heterocyclic nitrogen compound found in drugs?

Accepted Answer

Pyridine

Chapter 15: Amines – Structure, Properties, and Biological Importance

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