Question 1

Which of the following statements best describes the mechanism of base-catalyzed transesterification of esters?

Accepted Answer

It involves nucleophilic acyl substitution where the nucleophile is an alkoxide ion, forming a tetrahedral intermediate before elimination of the leaving group.

Question 2

During the saponification of a triglyceride, which of the following products is formed?

Accepted Answer

Glycerol and three molecules of fatty acid salts (soap)

Question 3

Which reagent is commonly used to reduce esters to primary alcohols?

Accepted Answer

LiAlH$$_4$$

Question 4

What is the main difference between the hydrolysis of acid chlorides and amides under aqueous conditions?

Accepted Answer

Acid chlorides hydrolyze rapidly under neutral conditions, while amides require either acidic or basic conditions and are less reactive.

Question 5

Which of the following best explains why saponification is irreversible?

Accepted Answer

The carboxylate ion formed is stabilized and cannot react further to reform the ester under basic conditions.

Question 6

In the acid-catalyzed hydrolysis of amides, which step involves the formation of a tetrahedral intermediate?

Accepted Answer

Addition of water to the protonated amide carbonyl

Question 7

Which product is obtained when a nitrile is hydrolyzed under acidic conditions?

Accepted Answer

Carboxylic acid and ammonium ion

Question 8

What is the role of DIBAL-H in the reduction of esters?

Accepted Answer

It selectively reduces esters to aldehydes at low temperatures.

Question 9

Which organometallic reagent reacts with acid chlorides to form ketones in a single addition?

Accepted Answer

Gilman reagent ($$R_2CuLi)$$

Question 10

In a Claisen condensation, which base is typically used to generate the enolate ion from an ester?

Accepted Answer

An alkoxide ion corresponding to the ester group

Question 11

Which of the following statements about the reactivity of acid derivatives is correct?

Accepted Answer

Acid chlorides are more reactive than anhydrides, esters, and amides toward nucleophilic substitution.

Question 12

What is the major organic product when ethyl propionate is treated with NaOH?

Accepted Answer

Sodium propionate and ethanol

Question 13

Which step in the mechanism of ester hydrolysis under basic conditions is responsible for the formation of the carboxylate ion?

Accepted Answer

Elimination of the alkoxide from the tetrahedral intermediate

Question 14

Which of the following is a correct statement about the Claisen condensation?

Accepted Answer

It requires esters with alpha hydrogens and a strong base to form β-ketoesters.

Question 15

What is the product of the reaction between methyl benzoate and ethyl acetate in the presence of sodium ethoxide?

Accepted Answer

Ethyl benzoate

Question 16

Which of the following best describes the outcome when a Grignard reagent reacts with an ester?

Accepted Answer

Two equivalents of Grignard add, resulting in a tertiary alcohol after workup.

Question 17

Which of the following is the correct order of reactivity for acid derivatives toward nucleophilic acyl substitution?

Accepted Answer

$$RCOCl \u003e (RCO)_2O \u003e RCOOR' \u003e RCONH_2$$

Question 18

What is the main product when an acid chloride reacts with $$(CH_3)_2CuLi ($$Gilman reagent)?

Accepted Answer

A ketone

Question 19

Which of the following is true about the reduction of nitriles with LiAlH$$_4$$?

Accepted Answer

It produces a primary amine after hydrolysis.

Question 20

In the mechanism of basic hydrolysis of amides, what is the fate of the nitrogen atom?

Accepted Answer

It is released as ammonia or an amine.

Interconversion and Reactions of Acid Derivatives in Organic Chemistry

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