Question 1

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

Accepted Answer

The resonance and polarity of the C=O bond create a partial positive charge on the carbonyl carbon.

Question 2

Which IR absorption is most characteristic of the C=O stretch in a simple ketone?

Accepted Answer

$1700\ 	ext{cm}^{-1}$

Question 3

A chemist wants to convert a nitrile ($R-CN$) to an aldehyde. Which reagent should they use?

Accepted Answer

DIBAL-H

Question 4

Which of the following is the correct IUPAC name for the compound $CH_3CH_2COH$?

Accepted Answer

Propanal

Question 5

In the mechanism of acetal formation from an aldehyde, which intermediate is formed after the first nucleophilic addition?

Accepted Answer

Hemiacetal

Question 6

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

Accepted Answer

NaBH\_4

Question 7

A student observes two weak IR absorptions near $2700$ and $2800\ 	ext{cm}^{-1}$ in a compound. What functional group is most likely present?

Accepted Answer

Aldehyde

Question 8

Which of the following reactions is used to convert an aldehyde to a carboxylic acid?

Accepted Answer

Oxidation with Jones reagent (CrO\_3/H\_2SO\_4)

Question 9

Which statement best describes the difference between the reactivity of aldehydes and ketones toward nucleophilic addition?

Accepted Answer

Aldehydes are generally more reactive due to less steric hindrance and greater partial positive charge on the carbonyl carbon.

Question 10

Which of the following is a correct description of the Wittig reaction?

Accepted Answer

Conversion of a carbonyl compound to an alkene using a phosphonium ylide

Question 11

Which of the following is a common protecting group for carbonyls in multistep synthesis?

Accepted Answer

Acetal

Question 12

A chemist wants to synthesize a ketone from a secondary alcohol. Which reagent would be most appropriate?

Accepted Answer

Jones reagent (CrO\_3/H\_2SO\_4)

Question 13

Which of the following statements about the resonance in amines is correct?

Accepted Answer

Aromatic amines have resonance delocalization that decreases basicity compared to aliphatic amines.

Question 14

Which IR absorption is most characteristic of an N-H stretch in a primary amine?

Accepted Answer

$3300\ 	ext{cm}^{-1}$

Question 15

Which of the following mechanisms is involved in the formation of an imine from an aldehyde and a primary amine?

Accepted Answer

Nucleophilic addition followed by elimination of water

Question 16

Which factor most strongly affects the basicity of an amine?

Accepted Answer

Resonance delocalization and inductive effects of substituents

Question 17

A chemist is planning a multistep synthesis involving the conversion of a carbonyl to an amine. Which sequence of reactions is most appropriate?

Accepted Answer

Formation of an imine followed by reduction

Question 18

Which of the following is the correct order of basicity for the following amines: primary, secondary, tertiary?

Accepted Answer

Secondary > primary > tertiary

Question 19

Which reagent is used in the Hofmann elimination to convert a quaternary ammonium salt to an alkene?

Accepted Answer

Ag\_2O and heat

Question 20

Which of the following statements about the nucleophilic addition to carbonyls is correct?

Accepted Answer

Nucleophilic attack occurs at the carbonyl carbon due to its partial positive charge.

Ketones, Aldehydes, and Amines: Structure, Reactivity, Synthesis, and Applications

Study Guide - Practice Questions