Question 1

Which of the following statements best describes the rate law for an E1 reaction?

Accepted Answer

The rate is proportional only to the concentration of the substrate: $$	ext{rate} = k[	ext{substrate}]$$

Question 2

Which of the following conditions will most favor an E1 elimination over an $$S_N1$$ substitution?

Accepted Answer

High temperature and a weak base

Question 3

During an E1 reaction, which step is the rate-determining step (RDS)?

Accepted Answer

Formation of the carbocation intermediate by leaving group departure

Question 4

Which of the following best explains why E1 reactions are regioselective for the more substituted alkene?

Accepted Answer

The more substituted alkene is more stable due to hyperconjugation and follows Zaitsev's Rule

Question 5

Which of the following solvents would most enhance the rate of an E1 reaction?

Accepted Answer

Ethanol ($$\mathrm{CH_3CH_2OH})$$

Question 6

A secondary carbocation is formed during an E1 reaction. Which rearrangement is most likely to occur if a tertiary carbon is adjacent?

Accepted Answer

1,2-hydride shift

Question 7

Which of the following statements about the stereochemistry of E1 reactions is correct?

Accepted Answer

Both cis and trans isomers are formed, but trans is usually the major product

Question 8

Why can't alcohols directly undergo E1 or $$S_N1$$ reactions without modification?

Accepted Answer

The hydroxide ion ($$\mathrm{OH^-}) is a $$poor leaving group and too unstable

Question 9

Which reagent is commonly used to convert an alcohol into a better leaving group for substitution or elimination reactions?

Accepted Answer

Tosyl chloride ($$\mathrm{TsCl}) $$with pyridine

Question 10

Which of the following acids will favor E1 dehydration of alcohols rather than substitution?

Accepted Answer

Sulfuric acid ($$\mathrm{H_2SO_4})$$

Question 11

Which of the following is the correct mechanism for tosylate ester formation from an alcohol?

Accepted Answer

Alcohol reacts with tosyl chloride in the presence of pyridine via an $$S_N2-$$like mechanism

Question 12

Which of the following is a related sulfonate ester that can be used as a leaving group, similar to tosylate?

Accepted Answer

Methanesulfonate (mesylate, $$\mathrm{OMs})$$

Question 13

A tertiary alcohol is treated with $$\mathrm{H_2SO_4}$$ and heat. What is the major organic product?

Accepted Answer

A tertiary alkene formed by E1 dehydration

Question 14

Which of the following best describes the difference between E1 and E2 mechanisms?

Accepted Answer

E1 is stepwise and E2 is concerted

Question 15

In an E1 reaction, what is the effect of increasing the strength of the base?

Accepted Answer

It has little to no effect on the rate of the reaction

Question 16

Which of the following is true regarding carbocation rearrangements in E1 reactions?

Accepted Answer

Carbocation rearrangements can lead to more stable carbocations and affect the major product

Question 17

Which of the following is the best leaving group for substitution and elimination reactions?

Accepted Answer

Tosylate ($$\mathrm{OTs})$$

Question 18

Which of the following statements is correct regarding the competition between E1 and $$S_N1$$ reactions?

Accepted Answer

E1 and $$S_N1$$ occur on the same substrates and have the same rate-determining step

Question 19

Which of the following is a correct statement about the use of tosylates in organic synthesis?

Accepted Answer

Tosylates are highly resonance stabilized and excellent leaving groups

E1 Reaction Mechanism, Carbocation Rearrangement, and Alcohols as Leaving Groups

Study Guide - Practice Questions