Question 1

Which of the following carboxylic acid derivatives is the most reactive toward nucleophilic acyl substitution?

Accepted Answer

RCOCl (acyl chloride)

Question 2

Which of the following best explains why amides have higher boiling points than esters?

Accepted Answer

Amides can form extensive intermolecular hydrogen bonds.

Question 3

In the nucleophilic acyl substitution mechanism, what determines which group is eliminated from the tetrahedral intermediate?

Accepted Answer

The group with the lowest basicity (weakest base) is eliminated.

Question 4

Which of the following correctly ranks the relative reactivities of carboxylic acid derivatives toward nucleophilic acyl substitution (from most to least reactive)?

Accepted Answer

$$ \mathrm{RCOCl} \u003e \mathrm{RCOOR'} \u003e \mathrm{RCOOH} \u003e \mathrm{$$RCONH_2$$} $$

Question 5

Which of the following statements about the resonance structures of carboxylic acid derivatives is correct?

Accepted Answer

Esters, carboxylic acids, and amides all have two significant resonance contributors.

Question 6

Why does the hydrolysis of an ester in basic conditions (saponification) proceed irreversibly?

Accepted Answer

The carboxylate ion formed is a poor electrophile and does not react with nucleophiles.

Question 7

Which of the following best describes the role of a catalyst in acid-catalyzed ester hydrolysis?

Accepted Answer

It protonates the carbonyl oxygen, making the carbonyl carbon more electrophilic.

Question 8

A student attempts to react an ester with chloride ion ($$ \mathrm{Cl^-} ) in $$the absence of a catalyst. What is the expected outcome?

Accepted Answer

No reaction occurs because $$ \mathrm{Cl^-}  is a $$weaker base than $$ \mathrm{RO^-} .$$

Question 9

Which of the following is a correct statement about the boiling points of carboxylic acid derivatives?

Accepted Answer

Amides have the highest boiling points due to strong hydrogen bonding.

Question 10

Which of the following best explains why acyl chlorides are more reactive than esters toward nucleophilic acyl substitution?

Accepted Answer

Chloride is a weaker base and a better leaving group than alkoxide.

Question 11

Which of the following reactions is an example of a transesterification?

Accepted Answer

$$ \mathrm{RCOOR'} + \mathrm{R''OH} \xrightarrow{HCl} \mathrm{RCOOR''} + \mathrm{R'OH} $$

Question 12

Which of the following best describes the mechanism of aspirin's inhibition of cyclooxygenase (COX)?

Accepted Answer

Aspirin acetylates a serine residue in the active site via transesterification.

Question 13

Which of the following statements about the hydrolysis of amides is correct?

Accepted Answer

Amides require acid or base catalysis for hydrolysis due to their low reactivity.

Question 14

A carboxylic acid is heated with an amine. What is the final product after heating?

Accepted Answer

An amide

Question 15

Which of the following best describes the decarboxylation of a β-keto acid?

Accepted Answer

It produces a ketone and carbon dioxide.

Question 16

Which of the following is true regarding the formation of acid anhydrides from carboxylic acids?

Accepted Answer

It requires the removal of water from two carboxylic acid molecules.

Question 17

Which of the following best explains why dicarboxylic acids have two different pKa values?

Accepted Answer

The first deprotonation is easier due to electron withdrawal by the neighboring carboxyl group, while the second is harder due to electrostatic repulsion.

Question 18

Which of the following statements about the Gabriel synthesis is correct?

Accepted Answer

It is used to synthesize primary amines from phthalimide and an alkyl halide.

Reactions and Properties of Carboxylic Acids and Their Derivatives

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