Question 1

Which of the following is the correct IUPAC name for the compound shown below?

$$\mathrm{CH_3CH_2COCH_2CH_3}$$

Accepted Answer

2-pentanone

Question 2

Which of the following statements best explains why aldehydes are generally more reactive toward nucleophilic addition than ketones?

Accepted Answer

Aldehydes are less sterically hindered and have a more polarized carbonyl group than ketones.

Question 3

What is the product of the following reaction?

$$\mathrm{CH_3CH_2C \equiv CH} (1-$$butyne) + $$\mathrm{1.} \ \mathrm{BH_3$} \ \mathrm{2.} \ \mathrm{H_2O_2, OH^-}$$

Accepted Answer

Butanal

Question 4

Which of the following nucleophiles would react most rapidly with benzaldehyde?

Accepted Answer

$$\mathrm{CH_3MgBr}$$

Question 5

A student attempts to react a Grignard reagent with a carboxylic acid. What is the most likely outcome?

Accepted Answer

The Grignard reagent will be protonated by the carboxylic acid, destroying the Grignard reagent.

Question 6

Which of the following best describes the role of the Bürgi–Dunitz angle in nucleophilic addition to carbonyls?

Accepted Answer

It is the optimal angle (about $$107^{\circ}) $$for nucleophilic attack to maximize overlap with the $$\pi^*$$ orbital of the carbonyl.

Question 7

Which of the following reagents will selectively oxidize a primary alcohol to an aldehyde without further oxidation to a carboxylic acid?

Accepted Answer

PCC (Pyridinium chlorochromate)

Question 8

Which of the following statements about hydrate formation from aldehydes and ketones is correct?

Accepted Answer

Hydrate formation is favored for aldehydes over ketones due to less steric hindrance and greater electrophilicity.

Question 9

Which of the following best describes the difference between the mechanisms of nucleophilic addition to carbonyls by strong versus weak nucleophiles?

Accepted Answer

Strong nucleophiles attack directly, while weak nucleophiles require activation of the carbonyl by acid.

Question 10

Which of the following is the correct product of the Wittig reaction between benzaldehyde and methyltriphenylphosphonium ylide?

Accepted Answer

Styrene ($$\mathrm{C_6H_5CH=CH_2$})$$

Question 11

Which of the following statements about the selectivity of the Wittig reaction is correct?

Accepted Answer

Stabilized ylides give predominantly trans (E) alkenes, while unstabilized ylides give cis (Z) alkenes.

Question 12

Which of the following best explains why acetals are used as protecting groups for aldehydes and ketones?

Accepted Answer

Acetals are stable to base and nonreactive under neutral or basic conditions, but can be removed with acid.

Question 13

Which of the following reagents will reduce a ketone to a secondary alcohol but will not reduce an ester?

Accepted Answer

NaBH$$_4$$

Question 14

Which of the following is the correct IUPAC name for the compound shown below?

$$\mathrm{ClCH_2CH_2COCH_2CH_3}$$

Accepted Answer

3-chloropentan-2-one

Question 15

Which of the following best describes the effect of resonance donation by a lone pair on a carbonyl compound?

Accepted Answer

It decreases the electrophilicity of the carbonyl carbon.

Question 16

Which of the following is the correct product of the reaction of 2-butanone with NaBH$$_4$$ followed by H$$_2O$$?

Accepted Answer

2-butanol

Question 17

Which of the following best explains why hydrate formation from acetone is less favored than from formaldehyde?

Accepted Answer

Acetone is more sterically hindered and less electrophilic than formaldehyde.

Question 18

Which of the following is the correct mechanism for the acid-catalyzed formation of a hemiacetal from an aldehyde and an alcohol?

Accepted Answer

Protonation of the carbonyl oxygen, nucleophilic attack by alcohol, deprotonation to form the hemiacetal.

Question 19

Which of the following best describes the effect of removing water during acetal formation?

Accepted Answer

It drives the equilibrium toward acetal formation by Le Chatelier's principle.

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

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