Question 1

Which of the following statements best describes the Zaitsev (Saytzeff) rule in E2 elimination reactions?

Accepted Answer

The major product is the most substituted alkene formed by elimination.

Question 2

Which of the following alcohols will undergo an $$\mathrm{S_N1}$$ reaction most rapidly when treated with HBr?

Accepted Answer

tert-butanol

Question 3

In an E2 elimination reaction, which of the following factors will increase the rate of reaction?

Accepted Answer

Using a strong base and increasing the concentration of the substrate

Question 4

Which of the following is true regarding the mechanism of $$\mathrm{S_N2}$$ reactions?

Accepted Answer

The reaction occurs in a single concerted step involving both the nucleophile and the substrate.

Question 5

Which of the following statements about the deuterium isotope effect in E2 reactions is correct?

Accepted Answer

Substitution of $$-D$$ for $$-H$$ results in a decrease in reaction rate.

Question 6

Which of the following best explains why benzylic and allylic halides undergo $$\mathrm{S_N1}$$ reactions more rapidly than alkyl halides?

Accepted Answer

Their carbocation intermediates are stabilized by resonance.

Question 7

A tertiary alcohol is treated with HCl. Which mechanism is most likely for the formation of the corresponding alkyl chloride?

Accepted Answer

$$\mathrm{S_N1}$$

Question 8

Which of the following statements about E1 reactions is correct?

Accepted Answer

E1 reactions proceed via a carbocation intermediate and are favored by weak bases.

Question 9

Which of the following is a key difference between $$\mathrm{S_N1}$$ and $$\mathrm{S_N2}$$ mechanisms?

Accepted Answer

$$\mathrm{S_N2}$$ reactions are stereospecific and result in inversion of configuration, while $$\mathrm{S_N1}$$ reactions can lead to racemization.

Question 10

Which of the following alkyl halides will react fastest in an $$\mathrm{S_N2}$$ reaction with NaI in acetone?

Accepted Answer

ethyl chloride

Question 11

Which of the following statements about the addition of HBr to alkynes is correct?

Accepted Answer

The reaction produces a geminal dihalide when excess HBr is used.

Question 12

Which of the following is the correct order of reactivity for alkyl halides in $$\mathrm{S_N2}$$ reactions?

Accepted Answer

primary \u003e secondary \u003e tertiary

Question 13

Which of the following is a consequence of the anti-periplanar geometry requirement in E2 reactions?

Accepted Answer

The leaving group and the hydrogen must be on opposite sides (anti) in the same plane for elimination to occur.

Question 14

Which of the following best describes the role of resonance in stabilizing carbocations during $$\mathrm{S_N1}$$ reactions?

Accepted Answer

Resonance stabilizes carbocations by delocalizing positive charge over multiple atoms.

Question 15

Which of the following is true about the reduction of alkynes using Na/NH$$_3 ($$dissolving metal reduction)?

Accepted Answer

It produces a trans-alkene as the major product.

Question 16

Which of the following statements about tautomerization of alkynes is correct?

Accepted Answer

Tautomerization converts an enol form to a keto form.

Question 17

Which of the following is a correct statement about the Lindlar catalyst in alkyne reduction?

Accepted Answer

It reduces alkynes to cis-alkenes.

Question 18

Which of the following is a good nucleophile for $$\mathrm{S_N2}$$ reactions?

Accepted Answer

Methoxide ion ($$\mathrm{CH_3O^-})$$

Question 19

Which of the following statements about the leaving group in nucleophilic substitution reactions is correct?

Accepted Answer

A good leaving group is a weak base with a low pKa.

Elimination and Alkyne Chemistry: E1, E2, and Alkyne Reactions

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