Question 1

Which of the following carbocations is expected to be the most stable due to hyperconjugation and inductive effects?

Accepted Answer

A tertiary carbocation: $$(CH_3$)_3C^+$$

Question 2

Which factor most significantly increases the rate of an $$S_N1$$ reaction?

Accepted Answer

Using a polar protic solvent

Question 3

In an $$E2$$ elimination reaction, which of the following is required for the reaction to proceed efficiently?

Accepted Answer

The leaving group and the hydrogen to be eliminated must be anti-periplanar

Question 4

Which of the following best describes the transition state of an $$E2$$ elimination reaction?

Accepted Answer

It is concerted, with bond breaking and bond formation occurring simultaneously

Question 5

A student is analyzing the reaction coordinate diagram for an $$S_N2$$ reaction. Which feature should they expect to see?

Accepted Answer

A single transition state with no intermediates

Question 6

Which of the following statements about $$S_N2$$ reactions is correct?

Accepted Answer

The reaction proceeds with inversion of configuration at the reactive center

Question 7

Which of the following is a correct example of a multi-step synthesis involving both substitution and elimination reactions?

Accepted Answer

Conversion of 1-bromopropane to 1-propanol via $$S_N2$$ substitution, then to propene via $$E2$$ elimination

Question 8

Which of the following reagents would best facilitate the $$E2$$ elimination of 2-bromobutane to form 2-butene?

Accepted Answer

Potassium tert-butoxide ($$KOtBu) in$$ $$t-$$butanol

Question 9

Which of the following statements about Markovnikov's rule is correct?

Accepted Answer

In the addition of $$HBr to $$propene, the hydrogen atom attaches to the less substituted carbon

Question 10

Which of the following is a key difference between $$S_N1$$ and $$S_N2$$ mechanisms?

Accepted Answer

$$S_N1$$ reactions involve a carbocation intermediate, while $$S_N2$$ reactions do not

Question 11

Which of the following best explains why tertiary alkyl halides undergo $$S_N1$$ reactions more readily than $$S_N2$$ reactions?

Accepted Answer

Steric hindrance prevents nucleophilic attack in $$S_N2$$ reactions

Question 12

Which of the following is the correct order of leaving group ability for the halides in nucleophilic substitution reactions?

Accepted Answer

$$I^- \u003e Br^- \u003e Cl^- \u003e F^-$$

Question 13

Which of the following statements about carbocation rearrangements is correct?

Accepted Answer

Carbocation rearrangements can involve hydride or alkyl shifts

Question 14

A chemist wants to synthesize tert-butyl chloride from tert-butyl alcohol. Which reagent should they use?

Accepted Answer

$$HCl$$

Question 15

Which of the following is a correct statement about the stereochemistry of $$E2$$ elimination reactions?

Accepted Answer

The reaction requires the leaving group and the hydrogen to be anti-periplanar

Question 16

Which of the following best describes the energy profile of a multi-step reaction with two transition states and one intermediate?

Accepted Answer

The diagram shows two peaks separated by a valley

Question 17

Which of the following is a correct example of a carbocation rearrangement?

Accepted Answer

A methyl shift from a secondary to a tertiary carbocation

Question 18

Which of the following is a correct statement about the role of solvents in $$S_N2$$ reactions?

Accepted Answer

Polar aprotic solvents increase the rate of $$S_N2$$ reactions

Question 19

Which of the following is the major product when 2-bromopropane is treated with a strong base?

Accepted Answer

Propene

Question 20

Which of the following is a correct statement about the use of $$PBr_3 in $$organic synthesis?

Accepted Answer

$$PBr_3$$ converts primary and secondary alcohols to alkyl bromides

Study Guide: Chapters 5–9 – Alkenes, Alkynes, Substitution & Elimination, and Multistep Synthesis

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