Question 1

Which of the following statements best explains why tertiary alkyl halides favor E2 elimination over E1 elimination when reacted with a strong base such as $$\mathrm{KOtBu}$$?

Accepted Answer

E2 elimination is favored because the reaction occurs in a single concerted step, minimizing carbocation rearrangement.

Question 2

Which of the following bases would most likely result in a Hofmann product during E2 elimination of a bulky alkyl halide?

Accepted Answer

$$\mathrm{KOtBu} ($$potassium tert-butoxide)

Question 3

A student reacts 2-bromobutane with sodium ethoxide ($$\mathrm{NaOEt}) in $$ethanol. Which major product is expected?

Accepted Answer

2-butene (Zaitsev product)

Question 4

Which factor most strongly influences the rate of E2 elimination reactions?

Accepted Answer

The concentration of the base

Question 5

Which of the following statements about the stereochemistry of E2 reactions is correct?

Accepted Answer

E2 reactions require the leaving group and the hydrogen to be anti-periplanar.

Question 6

Which substrate would most likely undergo E1 elimination rather than E2 when treated with a weak base?

Accepted Answer

tert-butyl bromide ($$\mathrm{(CH_3$)_3CBr})$$

Question 7

During the dehydration of 2-butanol using acid, which intermediate is formed?

Accepted Answer

A carbocation

Question 8

Which of the following best describes the product distribution in an E2 reaction using a bulky base?

Accepted Answer

The less substituted alkene (Hofmann product) is favored.

Question 9

Which of the following is a key difference between E1 and E2 elimination mechanisms?

Accepted Answer

E1 involves a carbocation intermediate, while E2 is a concerted process.

Question 10

A chemist wants to synthesize a terminal alkyne from a dihalide. Which reagent should be used to convert the dihalide to the alkyne?

Accepted Answer

$$\mathrm{$$NaNH_2$$} ($$sodium amide)

Question 11

Which of the following statements about the hydrogenation of alkenes is correct?

Accepted Answer

Hydrogenation with a metal catalyst produces syn-addition, forming cis-alkanes.

Question 12

Which of the following is the best explanation for why E2 reactions are favored at high temperatures?

Accepted Answer

High temperatures favor elimination because elimination increases entropy.

Question 13

Which of the following is true regarding the anti-addition of hydrogen to alkynes using sodium in liquid ammonia?

Accepted Answer

It produces trans-alkenes.

Question 14

Which of the following statements about carbocation rearrangements in E1 reactions is correct?

Accepted Answer

Carbocation rearrangements can occur in E1 reactions, leading to more stable carbocations.

Question 15

Which of the following is a common misconception about the E2 mechanism?

Accepted Answer

E2 reactions require a carbocation intermediate.

Question 16

A student is asked to predict the major product of the reaction between 2-chloro-2-methylpropane and water. Which mechanism is most likely and what is the major product?

Accepted Answer

E1 mechanism; 2-methylpropene

Question 17

Which of the following statements best describes the role of the leaving group in elimination reactions?

Accepted Answer

A good leaving group increases the rate of elimination.

Question 18

Which of the following is the correct order of alkyl halide reactivity in E2 elimination reactions?

Accepted Answer

Tertiary \u003e Secondary \u003e Primary

Question 19

Which of the following is a key requirement for a substrate to undergo E2 elimination?

Accepted Answer

The substrate must have a hydrogen anti-periplanar to the leaving group.

Question 20

Which of the following statements about the synthesis of alkynes by double elimination is correct?

Accepted Answer

Double elimination of a vicinal or geminal dihalide with $$\mathrm{$$NaNH_2$$}$$ produces an alkyne.

Organic Chemistry: Alkene Reactions, Stereochemistry, and Mechanisms (E2/E1)

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