Question 1

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

Accepted Answer

Acyl chloride, because the leaving group (Cl−) is the weakest base.

Question 2

What is the correct IUPAC name for the following compound: $$\mathrm{CH_3CH_2COOH}$$?

Accepted Answer

Propanoic acid

Question 3

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

Accepted Answer

Amides can form stronger intermolecular hydrogen bonds due to the presence of both N-H and C=O groups.

Question 4

Which of the following is the correct order of leaving group ability (from best to worst) for carboxylic acid derivatives?

Accepted Answer

$$\mathrm{Cl^- \u003e OR^- \u003e OH^- \u003e NH_2$^-}$$

Question 5

A student wants to synthesize an amide from a carboxylic acid. Which sequence of reagents would be most effective?

Accepted Answer

Convert the carboxylic acid to an acyl chloride, then react with ammonia.

Question 6

Which of the following best describes the mechanism of nucleophilic acyl substitution for carboxylic acid derivatives?

Accepted Answer

The nucleophile attacks the carbonyl carbon, forming a tetrahedral intermediate, followed by elimination of the leaving group.

Question 7

Which of the following compounds cannot undergo nucleophilic acyl substitution?

Accepted Answer

Ketone

Question 8

What is the product when ethanoic anhydride reacts with excess ethanol?

Accepted Answer

Two equivalents of ethyl acetate

Question 9

Which of the following best explains why acid-catalyzed hydrolysis of an ester is reversible, but base-promoted hydrolysis is not?

Accepted Answer

The carboxylate ion formed in base-promoted hydrolysis is unreactive toward nucleophilic attack.

Question 10

Which of the following is the correct systematic name for the compound with the structure $$\mathrm{CH_3CONH_2}$$?

Accepted Answer

Ethanamide

Question 11

A chemist wants to convert a carboxylic acid to an ester. Which of the following methods is most appropriate?

Accepted Answer

React the carboxylic acid with an alcohol in the presence of an acid catalyst (Fischer esterification).

Question 12

Which of the following best describes the effect of protonating the carbonyl oxygen in an ester during acid-catalyzed hydrolysis?

Accepted Answer

It increases the electrophilicity of the carbonyl carbon, making it more susceptible to nucleophilic attack.

Question 13

Which of the following is the correct IUPAC name for the compound with the structure $$\mathrm{CH_3CH_2COCl}$$?

Accepted Answer

Propanoyl chloride

Question 14

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

Accepted Answer

The first ionization is easier due to electron withdrawal, but the second is harder due to electrostatic repulsion.

Question 15

Which of the following is the correct systematic name for the compound with the structure $$\mathrm{CH_3CH_2COOCH_3}$$?

Accepted Answer

Methyl propanoate

Question 16

Which of the following best describes the role of coenzyme A in biological acyl transfer reactions?

Accepted Answer

It forms a thioester with the acyl group, making it more reactive toward nucleophilic attack.

Question 17

Which of the following is the correct IUPAC name for the compound with the structure $$\mathrm{CH_3CH_2CN}$$?

Accepted Answer

Propanenitrile

Question 18

Which of the following best explains why carboxylate ions do not undergo nucleophilic acyl substitution?

Accepted Answer

Carboxylate ions are negatively charged and thus not electrophilic enough for nucleophilic attack.

Reactions and Nomenclature of Carboxylic Acids and Carboxylic Acid Derivatives

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