Question 1

Which of the following statements best explains why the carbonyl carbon in aldehydes and ketones is electrophilic?

Accepted Answer

The electronegative oxygen atom polarizes the carbonyl group, making the carbonyl carbon partially positive and electrophilic.

Question 2

What is the correct IUPAC name for the following compound: $$\mathrm{CH_3CH_2COCH_3}$$?

Accepted Answer

2-butanone

Question 3

Which of the following reagents can selectively reduce an acid chloride to an aldehyde without further reduction to an alcohol?

Accepted Answer

$$\mathrm{LiAlH[OC(CH_3$)_3]_3} ($$lithium tri-tert-butoxyaluminum hydride)

Question 4

Which of the following best describes the product when a ketone reacts with a primary amine ($$\mathrm{$$RNH_2$$}) $$under mildly acidic conditions?

Accepted Answer

An imine

Question 5

Which of the following compounds is a hemiacetal?

Accepted Answer

$$\mathrm{R_2C(OH)OR'}$$

Question 6

Why are aldehydes generally more reactive toward nucleophilic addition than ketones?

Accepted Answer

Aldehydes are less sterically hindered and their carbonyl carbon is more electrophilic due to only one alkyl group.

Question 7

Which of the following is the correct sequence of steps for protecting a ketone as an acetal during a multi-step synthesis?

Accepted Answer

1. Protect the ketone as an acetal; 2. Perform the desired reaction; 3. Remove the protecting group by hydrolysis.

Question 8

Which of the following best describes the product of the reaction between a ketone and a secondary amine ($$\mathrm{R_2NH}) $$under mildly acidic conditions?

Accepted Answer

An enamine

Question 9

What is the main advantage of the Wittig reaction over elimination reactions for alkene synthesis?

Accepted Answer

The Wittig reaction always gives a single constitutional isomer with the double bond at a predictable location.

Question 10

Which of the following statements about the IR spectrum of aldehydes and ketones is correct?

Accepted Answer

Aldehydes and ketones show a strong absorption near $$1700\ \mathrm{cm}^{-1}$$ due to the C=O stretch.

Question 11

Which of the following is the correct product when acetone reacts with HCN followed by hydrolysis with aqueous acid?

Accepted Answer

An $$\alpha-$$hydroxy acid

Question 12

Which of the following best describes the mechanism of nucleophilic addition to an aldehyde or ketone?

Accepted Answer

Nucleophile attacks the carbonyl carbon, forming a tetrahedral intermediate, followed by protonation of the oxygen.

Question 13

Which of the following is the correct IUPAC name for the compound with the structure $$\mathrm{C_6H_5COCH_3}$$?

Accepted Answer

Acetophenone

Question 14

Which of the following statements about the formation of acetals from aldehydes or ketones is correct?

Accepted Answer

Acetal formation is catalyzed by acids and is reversible.

Question 15

Which of the following best describes the difference between a benzyl group and a benzoyl group?

Accepted Answer

A benzyl group is $$\mathrm{C_6H_5CH_2-}$$ and a benzoyl group is $$\mathrm{C_6H_5CO-}.$$

Question 16

Which of the following is a common use of formaldehyde in industry and biology?

Accepted Answer

As a disinfectant and preservative for biological specimens

Question 17

Which of the following best describes the product of the reaction between a ketone and ethylene glycol in the presence of $$\mathrm{TsOH}$$?

Accepted Answer

A cyclic acetal

Question 18

Which of the following is the correct order of reactivity toward nucleophilic addition for the following compounds: formaldehyde, acetone, benzaldehyde?

Accepted Answer

Formaldehyde \u003e benzaldehyde \u003e acetone

Aldehydes and Ketones: Structure, Nomenclature, Synthesis, and Reactions

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