Question 1

Which of the following best describes the mechanism of acid-catalyzed esterification (Fischer esterification) of a carboxylic acid with an alcohol?

Accepted Answer

Nucleophilic attack of the alcohol on the carbonyl carbon, followed by elimination of water.

Question 2

Which reagent would most effectively catalyze the formation of an imine from a ketone and a primary amine?

Accepted Answer

A trace amount of acid, such as $$\mathrm{H_3O^+}$$

Question 3

In the alkylation of enolates, which of the following is the most important factor for achieving high selectivity for monoalkylation?

Accepted Answer

Using a strong, non-nucleophilic base such as $$\mathrm{LDA}$$ and a slight excess of the ketone.

Question 4

Which of the following statements about the Claisen condensation is correct?

Accepted Answer

It requires two esters, at least one of which must have an alpha hydrogen.

Question 5

A student attempts to synthesize a tertiary alcohol by reacting a Grignard reagent with an ester. Which of the following best explains the outcome?

Accepted Answer

The Grignard reagent adds twice to the ester, resulting in a tertiary alcohol after hydrolysis.

Question 6

Which of the following is a key difference between the aldol reaction under basic and acidic conditions?

Accepted Answer

Under basic conditions, the enolate ion is the nucleophile; under acidic conditions, the enol is the nucleophile.

Question 7

Which of the following best describes the product of the Michael addition between methyl vinyl ketone and diethyl malonate?

Accepted Answer

A 1,5-dicarbonyl compound

Question 8

In the alkylation of ammonia with methyl iodide, which product is formed in the highest yield if excess methyl iodide is used?

Accepted Answer

Tetramethylammonium iodide ($$\mathrm{[N(CH_3$)_4]^+ I^-})$$

Question 9

Which of the following is the major product when acetophenone undergoes bromination at the alpha position?

Accepted Answer

$$\mathrm{C_6H_5COCH_2Br}$$

Question 10

Which of the following is a necessary condition for the formation of a cyanohydrin from an aldehyde?

Accepted Answer

Presence of $$\mathrm{HCN} ($$hydrogen cyanide)

Question 11

Which of the following best explains why the formation of enamines is favored over imines when a secondary amine reacts with a ketone?

Accepted Answer

Secondary amines cannot form imines due to lack of a hydrogen on nitrogen for elimination.

Question 12

Which of the following is the correct product of the hydrolysis of an imine under acidic conditions?

Accepted Answer

A carbonyl compound and an amine

Question 13

Which of the following is the correct order of reactivity for the following compounds in nucleophilic addition reactions: aldehyde, ketone, ester?

Accepted Answer

Aldehyde \u003e Ketone \u003e Ester

Question 14

A student mixes benzaldehyde and acetone in the presence of base. Which reaction mechanism is most likely to occur?

Accepted Answer

A crossed aldol condensation

Question 15

Which of the following is the major product when diethyl malonate undergoes alkylation with methyl bromide followed by hydrolysis and decarboxylation?

Accepted Answer

Propanoic acid ($$\mathrm{CH_3CH_2COOH})$$

Question 16

Which of the following is the correct intermediate formed during the base-catalyzed hydrolysis of an ester?

Accepted Answer

Tetrahedral alkoxide intermediate

Question 17

Which of the following best describes the product of the reaction between acetone and ethyl acetoacetate under basic conditions?

Accepted Answer

A beta-diketone

Question 18

Which of the following is the correct product of the reaction between an aldehyde and $$\mathrm{$$NaBH_4$$}$$?

Accepted Answer

A primary alcohol

Question 19

Which of the following is the correct product of the reaction between acetone and ammonia under acidic conditions?

Accepted Answer

Imine

Question 20

Which of the following is the correct product when benzaldehyde reacts with $$\mathrm{HCN}$$?

Accepted Answer

Benzaldehyde cyanohydrin ($$\mathrm{C_6H_5CH(OH)CN})$$

Organic Chemistry Mechanisms for Exam Preparation

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