Question 1

Which of the following statements best explains why ethers are commonly used as solvents in organometallic reactions, such as Grignard reagent preparations?

Accepted Answer

Ethers act as Lewis bases, coordinating to metal cations and stabilizing organometallic reagents without reacting with them.

Question 2

A chemist attempts to synthesize tert-butyl propyl ether using sodium propoxide and tert-butyl bromide. What is the major product of this reaction, and why?

Accepted Answer

Isobutylene, because the strong base induces E2 elimination on the tertiary halide.

Question 3

Which of the following best describes the geometry and bond angle around the oxygen atom in a simple ether such as diethyl ether?

Accepted Answer

Bent geometry with a bond angle of approximately 110° due to sp3 hybridization.

Question 4

Which of the following ethers is most soluble in water, and why?

Accepted Answer

tert-Butanol, because it can both donate and accept hydrogen bonds with water.

Question 5

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

CH3—O—C(CH3)3

Accepted Answer

2-methoxy-2-methylpropane

Question 6

What is the main safety concern when storing ethers for long periods, and what precaution should be taken?

Accepted Answer

Ethers can oxidize to form explosive peroxides; store in full bottles with tight caps and avoid distilling to dryness.

Question 7

Which of the following statements about the cleavage of ethers by HI or HBr is correct?

Accepted Answer

The reaction involves protonation of the ether oxygen, followed by SN2 attack by the halide ion.

Question 8

Which of the following best explains why epoxides are more reactive toward nucleophilic ring opening than acyclic ethers?

Accepted Answer

Epoxides have significant ring strain, making ring opening thermodynamically favorable.

Question 9

A chemist wants to synthesize 2-methoxyhexane from 1-hexene. Which method would provide the best yield?

Accepted Answer

React 1-hexene with methanol in the presence of mercuric acetate, followed by reduction with NaBH4.

Question 10

Which of the following best describes the selectivity of epoxidation of dienes with peroxyacids?

Accepted Answer

The most electron-rich double bond reacts fastest, allowing for selective epoxidation.

Question 11

Which of the following is a correct statement about the acid-catalyzed opening of epoxides?

Accepted Answer

The nucleophile attacks the more substituted carbon because it is more electrophilic after protonation.

Question 12

Which of the following best explains why crown ethers can dissolve ionic salts in nonpolar organic solvents?

Accepted Answer

Crown ethers encapsulate metal cations, allowing the complex to dissolve in nonpolar solvents.

Question 13

Which of the following is the correct product for the base-catalyzed opening of 1,2-epoxycyclopentane with sodium ethoxide?

Accepted Answer

trans-2-ethoxy-1-methylcyclopentanol (attack at less hindered carbon)

Question 14

Which of the following is a correct statement about the Williamson ether synthesis?

Accepted Answer

It involves an SN2 reaction between an alkoxide and a primary alkyl halide.

Question 15

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

Cyclohexane ring with a methoxy group attached.

Accepted Answer

Methoxycyclohexane

Question 16

Which of the following best describes the product of the reaction between an epoxide and a Grignard reagent (RMgX) followed by aqueous workup?

Accepted Answer

A primary alcohol with the R group added to the less hindered carbon of the epoxide.

Ethers and Epoxides: Structure, Properties, and Reactions

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드