Question 1

Which of the following statements best explains why ethers have boiling points similar to alkanes of comparable size, despite the presence of an electronegative oxygen atom?

Accepted Answer

Ethers lack the ability to hydrogen bond with themselves, so their boiling points are similar to alkanes.

Question 2

Which method would be most appropriate for synthesizing tert-butyl methyl ether from 2-methylpropene and methanol?

Accepted Answer

Acid-catalyzed hydration of 2-methylpropene with methanol.

Question 3

Which of the following best describes the role of crown ethers in organic reactions?

Accepted Answer

They chelate cations, increasing the solubility of ionic salts in nonpolar solvents.

Question 4

In the Williamson ether synthesis, why is it important to use a primary alkyl halide rather than a secondary or tertiary one?

Accepted Answer

Secondary and tertiary alkyl halides tend to undergo E2 elimination rather than substitution.

Question 5

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

$$\mathrm{CH_3CH_2OCH_2CH_3}$$

Accepted Answer

Diethyl ether

Question 6

What is the major organic product when diethyl ether is heated with excess hydrobromic acid ($$\mathrm{HBr}$$)?

Accepted Answer

Ethyl bromide and ethanol

Question 7

Which of the following statements about the acid-catalyzed ring opening of epoxides is correct?

Accepted Answer

The nucleophile attacks the more substituted carbon, with inversion of configuration.

Question 8

A chemist wants to convert cyclohexene to trans-1,2-cyclohexanediol. Which sequence of reagents would accomplish this transformation?

Accepted Answer

1. Peracid (e.g., $$\mathrm{mCPBA}$$), 2. $$\mathrm{H_2O}$$, acid

Question 9

Which of the following best explains why epoxides are more reactive toward nucleophilic substitution than other ethers?

Accepted Answer

Epoxides have significant ring strain, making their carbons more electrophilic.

Question 10

Which of the following is the correct product of the reaction between 1-bromooctane and potassium fluoride in benzene with 18-crown-6?

Accepted Answer

1-Fluorooctane

Question 11

Which of the following statements about the oxidation of sulfides is correct?

Accepted Answer

Sulfides can be oxidized to sulfoxides with one equivalent of $$\mathrm{H_2O_2}.$$

Question 12

Which of the following best describes the product of the reaction between sodium methanethiolate ($$\mathrm{CH_3S^-Na^+}) $$and 1-chloropropane?

Accepted Answer

Propyl methyl sulfide

Question 13

Which spectroscopic feature is characteristic of ethers in infrared (IR) spectroscopy?

Accepted Answer

A band due to antisymmetric C-O-C stretch around 1100 cm$$^{-1}$$

Question 14

Which of the following is true regarding the stereochemistry of epoxidation with peracids?

Accepted Answer

Both C-O bonds form with syn stereospecificity.

Question 15

Which of the following best describes the product of the acid-catalyzed reaction of ethylene oxide with ethanol?

Accepted Answer

2-Ethoxyethanol

Question 16

Which of the following statements about the preparation of epoxides via vicinal halohydrin is correct?

Accepted Answer

The halohydrin is treated with base to generate an alkoxide, which attacks intramolecularly to form the epoxide.

Question 17

Which of the following is a correct statement about the $$^1H $$NMR chemical shift of protons adjacent to sulfur in sulfides compared to ethers?

Accepted Answer

Protons adjacent to sulfur appear further upfield (lower ppm) than those adjacent to oxygen.

Question 18

Which of the following best describes the mechanism of nucleophilic ring opening of epoxides under basic conditions?

Accepted Answer

The nucleophile attacks the less substituted carbon with inversion of configuration.

Question 19

Which of the following is the correct name for the sulfur analogue of oxirane?

Accepted Answer

Thirane

Ethers, Epoxides, and Sulfides: Structure, Nomenclature, Synthesis, and Reactivity

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