Question 1

Which of the following statements best explains why the carbon atom in a carbonyl group is highly susceptible to nucleophilic attack?

Accepted Answer

The carbonyl carbon is partially positive due to the electronegativity of the oxygen atom, making it an electrophilic center.

Question 2

Which of the following carbonyl compounds is most reactive toward nucleophilic addition?

Accepted Answer

Formaldehyde

Question 3

A student wants to prepare a Grignard reagent from 1-bromopropane. Which solvent should they use to ensure successful formation of the reagent?

Accepted Answer

Diethyl ether

Question 4

Which of the following best describes the product when methylmagnesium bromide (a Grignard reagent) reacts with formaldehyde followed by aqueous workup?

Accepted Answer

A primary alcohol

Question 5

Why are organometallic reagents such as Grignard and organolithium compounds typically prepared and used under anhydrous conditions?

Accepted Answer

They are strong bases and react rapidly with water, destroying the reagent.

Question 6

Which of the following correctly describes the difference in reactivity between aldehydes and ketones toward nucleophilic addition?

Accepted Answer

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

Question 7

A chemist wants to convert a carboxylic acid to a primary alcohol. Which reagent would be most effective for this transformation?

Accepted Answer

LiAlH\_4

Question 8

Which of the following best explains why tertiary alcohols cannot be prepared by the reaction of a Grignard reagent with formaldehyde?

Accepted Answer

Formaldehyde only has one carbon, so only primary alcohols can be formed.

Question 9

Which of the following statements about the reaction of organometallic reagents with epoxides is correct?

Accepted Answer

The nucleophile attacks the less hindered (less substituted) carbon of the epoxide.

Question 10

A chemist wants to selectively reduce an aldehyde in the presence of an ester. Which reagent should they use?

Accepted Answer

NaBH\_4

Question 11

Which of the following is a correct statement about the use of protecting groups in carbonyl chemistry?

Accepted Answer

Protecting groups are used to temporarily mask a reactive functional group to prevent unwanted reactions.

Question 12

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

Accepted Answer

An alkene

Question 13

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

Accepted Answer

Formaldehyde \u003e benzaldehyde \u003e acetone

Question 14

A chemist reacts 2 equivalents of methyl lithium with carbon dioxide, followed by aqueous workup. What is the major organic product?

Accepted Answer

Acetic acid

Question 15

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

Accepted Answer

Ketones have two electron-donating alkyl groups, which decrease the partial positive charge on the carbonyl carbon and increase steric hindrance.

Question 16

Which of the following is a correct statement about the reaction of Gilman reagents (organocuprates) with acid chlorides?

Accepted Answer

Gilman reagents react with acid chlorides to give ketones via nucleophilic acyl substitution.

Question 17

Which of the following best describes the mechanism of nucleophilic addition to a carbonyl group?

Accepted Answer

The nucleophile attacks the carbonyl carbon, forming a tetrahedral intermediate.

Question 18

A chemist wants to synthesize a secondary alcohol using a Grignard reagent. Which combination of starting materials would be appropriate?

Accepted Answer

Methylmagnesium bromide and acetaldehyde

Question 19

Which of the following is a correct statement about the use of PCC (pyridinium chlorochromate) in organic synthesis?

Accepted Answer

PCC oxidizes primary alcohols to aldehydes without further oxidation to carboxylic acids.

Question 20

Which of the following best describes the role of a protecting group in the synthesis of a molecule containing both an alcohol and a carbonyl group?

Accepted Answer

To prevent the alcohol from reacting with organometallic reagents by temporarily converting it to an unreactive derivative.

Organometallics and Reactions of Aldehydes & Ketones: Structure, Reactivity, and Nomenclature

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