Question 1

Which of the following statements best explains why tertiary alkyl halides favor the $$S_N1$$ mechanism over the $$S_N2$$ mechanism?

Accepted Answer

Tertiary alkyl halides form more stable carbocations, which is required for the $$S_N1$$ mechanism.

Question 2

In an $$E2$$ elimination reaction, which geometric requirement must be met for the reaction to proceed efficiently?

Accepted Answer

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

Question 3

Which of the following solvents would most likely favor an $$S_N2$$ reaction over an $$S_N1$$ reaction?

Accepted Answer

Acetone

Question 4

A secondary alkyl halide reacts with sodium ethoxide ($$NaOEt) in $$ethanol. Which major product is expected?

Accepted Answer

An alkene formed by $$E2$$ elimination

Question 5

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

Accepted Answer

$$OTs^- ($$tosylate)$

Question 6

In the $$E1$$ elimination mechanism, which step is rate-determining?

Accepted Answer

Loss of the leaving group to form a carbocation

Question 7

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

Accepted Answer

The reaction rate depends on both the substrate and nucleophile concentrations.

Question 8

Which product will be favored in an $$E2$$ elimination of 2-bromo-2-methylbutane with potassium tert-butoxide ($$t-$$BuOK)?

Accepted Answer

The least substituted alkene (Hofmann product)

Question 9

Which of the following best describes the role of a polar protic solvent in $$S_N1$$ reactions?

Accepted Answer

It stabilizes the carbocation intermediate, increasing the reaction rate.

Question 10

Which of the following is true regarding the stereochemistry of $$E2$$ eliminations?

Accepted Answer

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

Question 11

A primary alkyl halide reacts with a strong, non-bulky nucleophile in an aprotic solvent. Which mechanism is most likely?

Accepted Answer

$$S_N2$$

Question 12

Which of the following statements about the Zaitsev rule is correct?

Accepted Answer

The major product of elimination is always the most substituted alkene.

Question 13

Which of the following is a common method for generating epoxides from alkenes?

Accepted Answer

Reaction with $$m-$$CPBA (meta-chloroperoxybenzoic acid)

Question 14

In the $$S_N1$$ mechanism, which factor most strongly affects the rate of reaction?

Accepted Answer

Stability of the carbocation intermediate

Question 15

Which of the following statements about nucleophilicity and basicity is correct?

Accepted Answer

Nucleophilicity is a kinetic property, while basicity is a thermodynamic property.

Question 16

Which of the following is most likely to undergo rearrangement during an $$S_N1 or$$ $$E1$$ reaction?

Accepted Answer

A primary carbocation

Question 17

Which of the following reagents would convert a cyclohexene to a trans-1,2-dibromocyclohexane?

Accepted Answer

$$Br_2 in$$ $$CCl_4$$

Question 18

Which of the following best describes the product of oxymercuration-demercuration of an alkene?

Accepted Answer

An alcohol added to the more substituted carbon (Markovnikov)

Question 19

Which of the following is true about the stereochemistry of halohydrin formation from alkenes?

Accepted Answer

The halogen and hydroxyl group add to opposite sides of the double bond (anti addition).

Substitution and Elimination Reactions in Organic Chemistry: Mechanisms, Properties, and Applications

Study Guide - Practice Questions