A cyanohydrin: $$\text{(CH}_3)_2C(OH)CN$$

Question 1

Which of the following statements best describes the bonding and structure of the carbonyl group in aldehydes and ketones?

Accepted Answer

The carbonyl carbon is sp$$^2$$ hybridized, and the bond angle is approximately 120°.

Question 2

Which of the following compounds is correctly matched with its common name?

Accepted Answer

CH$$_3$$COCH$$_3$$: Acetone

Question 3

Which of the following statements about the physical properties of aldehydes and ketones is CORRECT?

Accepted Answer

Aldehydes and ketones have higher boiling points than alkanes of similar molecular weight but lower than alcohols.

Question 4

In IR spectroscopy, which of the following is the typical range for the C=O stretching frequency of an unconjugated ketone?

Accepted Answer

$$1710-1750\ 	ext{cm}^{-1}$$

Question 5

Which of the following reactions is best suited for the synthesis of a phenyl ketone such as acetophenone?

Accepted Answer

Friedel-Crafts Acylation

Question 6

Which reagent is commonly used to selectively reduce an acid chloride to an aldehyde without further reduction to a primary alcohol?

Accepted Answer

Rosenmund catalyst (H$$_2$$, Pd/BaSO$$_4)$$

Question 7

Which of the following statements about the nucleophilic addition to a carbonyl group is TRUE?

Accepted Answer

The nucleophile attacks the carbonyl carbon, breaking the C=O pi bond and forming a tetrahedral intermediate.

Question 8

Which of the following carbonyl compounds will react fastest with water to form a hydrate?

Accepted Answer

Formaldehyde

Question 9

What is the product when acetone reacts with HCN (hydrogen cyanide)?

Accepted Answer

A cyanohydrin: $$	ext{(CH}_3)_2C(OH)CN$$

Question 10

Which of the following is a Schiff base?

Accepted Answer

An imine formed from the reaction of a primary amine with a ketone

Question 11

Which of the following best describes the structure of an acetal?

Accepted Answer

A carbon atom bonded to two -OR groups, one alkyl group, and one -H or -R group

Question 12

Why are acetals commonly used as protecting groups for carbonyl compounds in organic synthesis?

Accepted Answer

They are stable under basic conditions and can be easily removed by acid.

Question 13

Which of the following sets of reagents would you use to perform a Wittig reaction to convert benzaldehyde to trans-stilbene?

Accepted Answer

Benzaldehyde and (C$$_6H$_5)$$CHPPh$$_3Br $$with base

Question 14

Which reagent is used in the Tollens test to distinguish aldehydes from ketones?

Accepted Answer

Ag(NH$$_3$$)$$_2^+ ($$Tollens' reagent)

Question 15

Which of the following statements about the reduction of carbonyl compounds is CORRECT?

Accepted Answer

LiAlH$$_4$$ can reduce aldehydes to primary alcohols and ketones to secondary alcohols.

Question 16

Which of the following is the correct sequence to synthesize a ketone from a carboxylic acid?

Accepted Answer

Carboxylic acid $$\rightarrow$$ acid chloride $$\rightarrow$$ organocuprate addition $$\rightarrow$$ ketone

Question 17

Which of the following best describes the McLafferty rearrangement observed in mass spectrometry of ketones?

Accepted Answer

A rearrangement involving transfer of a gamma hydrogen to the carbonyl oxygen, resulting in cleavage and formation of an alkene and an enol.

Question 18

Which of the following is the product of the Wolff-Kishner reduction of acetophenone?

Accepted Answer

Ethylbenzene

Question 19

Which of the following statements about the formation of imines from aldehydes or ketones is TRUE?

Accepted Answer

The reaction is a condensation reaction that requires a primary amine and acid catalyst.

Aldehydes and Ketones: Structure, Properties, Synthesis, and Reactions (Chapter 18 Study Guide)

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