Question 1

Which of the following statements best explains why ethers generally have lower boiling points than alcohols of similar molecular weight?

Accepted Answer

Ethers cannot form hydrogen bonds with themselves, unlike alcohols.

Question 2

What is the IUPAC name for the compound with the structure $$\mathrm{CH_3CH_2-O-CH_2CH_3}$$?

Accepted Answer

Diethyl ether

Question 3

Which of the following solvents would best solvate a lithium cation ($$\mathrm{Li^+}) $$but not a fluoride anion ($$\mathrm{F^-}$$)?

Accepted Answer

Diethyl ether

Question 4

A Grignard reagent is stabilized in solution by complexation with an ether. Which feature of the ether is most responsible for this stabilization?

Accepted Answer

The ether's nonbonding electron pairs on oxygen

Question 5

Which crown ether would best solvate a potassium ion ($$\mathrm{K^+}$$)?

Accepted Answer

18-crown-6

Question 6

Which IR absorption is characteristic of the C—O stretch in ethers?

Accepted Answer

$$\mathrm{1000-1200\ cm$$^{-1}$$}$$

Question 7

In the mass spectrometry of ethers, what is the main fragmentation pathway?

Accepted Answer

Alpha cleavage to form a resonance-stabilized oxonium ion

Question 8

Which of the following is a poor method for synthesizing tert-butyl propyl ether using the Williamson ether synthesis?

Accepted Answer

Reacting sodium propoxide with tert-butyl bromide

Question 9

What is the major product when diethyl ether is heated with concentrated HI?

Accepted Answer

Ethyl iodide

Question 10

Why does phenol not react further to become a halide during ether cleavage with HBr?

Accepted Answer

An SN2 reaction cannot occur on an sp2 carbon.

Question 11

Which precaution should be taken when storing ethers to prevent explosive accidents?

Accepted Answer

Store in full bottles with tight caps to minimize exposure to oxygen.

Question 12

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

$$\mathrm{CH_3$-O-C(CH_3$)_3}$$

Accepted Answer

2-Methyl-2-methoxypropane

Question 13

Which method is commonly used for the laboratory synthesis of ethers?

Accepted Answer

Williamson ether synthesis (SN2 attack of alkoxide on primary halide)

Question 14

What is the product of the oxidation of dimethyl sulfide with excess $$\mathrm{H_2O_2} in $$acetic acid?

Accepted Answer

Dimethyl sulfone

Question 15

Which of the following statements about thioethers (sulfides) is correct?

Accepted Answer

Thioethers can be synthesized by the Williamson ether synthesis using a thiolate ion.

Question 16

What is the main advantage of using silyl ethers as protecting groups for alcohols in organic synthesis?

Accepted Answer

Silyl ethers are easily formed and easily hydrolyzed.

Question 17

Which reagent is most commonly used for the selective epoxidation of alkenes?

Accepted Answer

Meta-chloroperoxybenzoic acid (MCPBA)

Question 18

During the acid-catalyzed ring opening of an epoxide, which carbon does the nucleophile attack?

Accepted Answer

The more electrophilic (more substituted) carbon

Question 19

What is the expected product when sodium ethoxide reacts with 1-methyl-1,2-epoxycyclopentane?

Accepted Answer

(E)-2-ethoxy-1-methylcyclopentanol

Question 20

Which of the following best describes the thermodynamic driving force for the base-catalyzed opening of epoxides?

Accepted Answer

Release of ring strain (about 25 kcal/mol)

Ethers, Epoxides, and Thioethers: Structure, Properties, and Reactions

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