Q: Which synthetic method would you use to convert a terminal alkyne to a methyl ketone?

Hydration with $$\text{Hg}^{2+}$$ and $$\text{H}_2\text{SO}_4$$

Q: Which of the following best describes the product of the Wittig reaction between benzaldehyde and methyltriphenylphosphonium ylide?

Styrene ($$\text{C}_6\text{H}_5\text{CH}=\text{CH}_2)$$

Question 1

Which of the following statements best explains why the C=O bond in a ketone is shorter and stronger than the C=C bond in an alkene?

Accepted Answer

The oxygen atom in the C=O bond is more electronegative than carbon, leading to greater orbital overlap and bond strength.

Question 2

Which of the following functional groups has the highest priority in IUPAC nomenclature?

Accepted Answer

Carboxylic acid

Question 3

Given the following IR spectrum data, which compound is most likely present: strong absorption at $$1710\ 	ext{cm}^{-1}$$ and weak absorption at $$2710\ 	ext{cm}^{-1}$$?

Accepted Answer

A simple aldehyde

Question 4

Which of the following compounds will show a $$^1	ext{H}$$ NMR signal at $$\delta = 9-10$$ ppm?

Accepted Answer

An aldehyde

Question 5

Which synthetic method would you use to convert a terminal alkyne to a methyl ketone?

Accepted Answer

Hydration with $$	ext{Hg}^{2+}$$ and $$	ext{H}_2	ext{SO}_4$$

Question 6

Which reagent can selectively oxidize a primary alcohol to an aldehyde without further oxidation to a carboxylic acid?

Accepted Answer

PCC (Pyridinium chlorochromate)

Question 7

A student wants to synthesize a ketone from a carboxylic acid. Which sequence of reagents would be most effective?

Accepted Answer

1. Thionyl chloride, 2. Lithium dialkyl cuprate

Question 8

Which of the following statements about the reactivity of aldehydes and ketones toward nucleophilic addition is correct?

Accepted Answer

Aldehydes are more reactive than ketones because the carbonyl carbon is less hindered and more electrophilic.

Question 9

Which product is formed when acetone reacts with propylmagnesium bromide followed by aqueous workup?

Accepted Answer

$$	ext{2-methyl-2-pentanol}$$

Question 10

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

Accepted Answer

A hydrogen atom from the gamma position migrates to the carbonyl oxygen, forming an alkene and a neutral fragment.

Question 11

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

Accepted Answer

They are generally more soluble in water than hydrocarbons of similar molecular weight.

Question 12

Which of the following reactions is used to completely reduce a carbonyl group to a methylene ($$-	ext{CH}_2-) $$group under basic conditions?

Accepted Answer

Wolff-Kishner reduction

Question 13

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

$$	ext{CH}_3	ext{CH}_2	ext{COCH}_2	ext{CH}_3$$

Accepted Answer

2-pentanone

Question 14

Which of the following statements about acetal formation is correct?

Accepted Answer

Acetals are used as protecting groups for carbonyl compounds because they are stable in base but can be removed in acid.

Question 15

Which of the following best describes the product of the Wittig reaction between benzaldehyde and methyltriphenylphosphonium ylide?

Accepted Answer

Styrene ($$	ext{C}_6	ext{H}_5	ext{CH}=	ext{CH}_2)$$

Question 16

Which test can be used to distinguish between an aldehyde and a ketone in the laboratory?

Accepted Answer

Tollens' test

Question 17

Which of the following is the correct condensed structure for formaldehyde?

Accepted Answer

$$	ext{CH}_2	ext{O}$$

Question 18

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

Accepted Answer

LiAlH$$_4$$ can reduce carboxylic acids, esters, and ketones.

Aldehydes and Ketones: Structure, Properties, and Reactions

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