Question 1

Which statement best explains why the carbonyl carbon in aldehydes and ketones is susceptible to nucleophilic attack?

Accepted Answer

The carbonyl carbon is partially positive due to the electronegative oxygen and its sp\^2 geometry, making it planar and accessible to nucleophiles.

Question 2

Which reagent is most selective for reducing aldehydes and ketones, but not esters or carboxylic acids?

Accepted Answer

NaBH\_4

Question 3

A primary alcohol is oxidized using PCC. What is the major product?

Accepted Answer

Aldehyde

Question 4

Which organometallic reagent is prepared by reacting an alkyl halide with magnesium in dry ether?

Accepted Answer

Grignard reagent

Question 5

What is the product when a Grignard reagent reacts with formaldehyde followed by aqueous workup?

Accepted Answer

Primary alcohol

Question 6

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 7

Which reagent is commonly used to oxidize secondary alcohols to ketones?

Accepted Answer

CrO\_3 in H\_2SO\_4 (chromic acid)

Question 8

What is the major product when methylmagnesium bromide reacts with acetone followed by water?

Accepted Answer

Tertiary alcohol

Question 9

Which organometallic reagent is best for performing 1,4-addition to an α,β-unsaturated carbonyl compound?

Accepted Answer

Organocuprate (Gilman reagent)

Question 10

Why must organometallic reagents be protected from water and protic solvents during reactions?

Accepted Answer

They are strong bases and will react with protons, destroying the reagent.

Question 11

Which of the following is the correct general formula for an ester functional group?

Accepted Answer

$$R-COO-R'$$

Question 12

A cyclic acetal is formed by reacting a carbonyl compound with which reagent?

Accepted Answer

A glycol (diol)

Question 13

Which statement about the Wittig reaction is correct?

Accepted Answer

It converts a carbonyl group into an alkene using a phosphonium ylide.

Question 14

Which of the following is a common protecting group for carbonyls during organometallic reactions?

Accepted Answer

Cyclic acetal

Question 15

What is the product when an organolithium reagent reacts with carbon dioxide followed by acid workup?

Accepted Answer

Carboxylic acid

Question 16

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

Accepted Answer

Aldehydes are more reactive because they are less substituted and have less steric hindrance.

Question 17

Which of the following is the correct mechanism for the formation of a hemiacetal under acid catalysis?

Accepted Answer

Protonation of the carbonyl oxygen, followed by nucleophilic attack by an alcohol.

Question 18

Which of the following is a plausible reason why secondary alcohols do not oxidize to aldehydes?

Accepted Answer

Secondary alcohols lack a hydrogen atom on the carbon bearing the OH group.

Question 19

Which of the following is the correct general reaction for the preparation of an organolithium reagent?

Accepted Answer

$$R-X + 2Li \rightarrow R-Li + LiX$$

Question 20

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

Accepted Answer

The organometallic reagent attacks the less hindered side of the epoxide, opening the ring.

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

Study Guide - Practice Questions