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

$I^- > Br^- > Cl^- > F^-$

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

Study Guide - Practice Questions