Deck 9: Substitution and Elimination Reactions of Alkyl Halides

Question 1

What happens in the following S_N2 reaction if the concentration of both reagents is doubled?

A) The reaction rate doubles.
B) The reaction rate triples.
C) The reaction rate is quadrupled.
D) The reaction rate is unaffected.
E) The reaction rate is halved.

Answer 1

The reaction rate is quadrupled.

Question 2

Which of the following factors favor an S_N2 reaction with a negatively charged nucleophile?

A) a good leaving group
B) a good nucleophile
C) an unhindered reaction center
D) an aprotic polar solvent
E) all of the above

Answer 2

all of the above

Question 3

Which of the following species is the best nucleophile in methanol?

A) F^?
B) NH₃
C) CH₃S^?
D) CH₃O^?
E) HO^?

Answer 3

CH₃S^?

Question 4

Which of the following substrates react fastest in an S_N2 reaction?

A) vinyl bromide
B) cyclohexyl bromide
C) phenyl iodide
D) 2-bromopropane
E) benzyl bromide

Question 5

Which of the following best explains a partial racemization?

A) a good leaving group
B) an S_N2 reaction
C) formation of an intimate ion pair
D) completely dissociated ions
E) a polar solvent

Question 6

Which of the following statements is not true about the S_N1 reaction of an alkyl halide?

A) Tertiary alkyl halides and benzyl and allyl halides undergo S_N1 reactions.
B) The rate is dependent upon the stability of the carbocation.
C) The rate is dependent upon the concentration of the nucleophile.
D) The reaction requires a good leaving group.
E) The reaction is favored in a polar protic solvent.

Question 7

Which of the following statements is false?

A) Increasing solvent polarity decreases the reaction rate when any reactant is charged.
B) Increasing solvent polarity increases the reaction rate when none of the reactants is charged.
C) An E2 reaction is favored by a high concentration of a strong, hindered base.
D) An E1 reaction is favored by a secondary alkyl halide.
E) An E2 is favored by a strong base.

Question 8

Which of the following compounds undergoes an E2 reaction most readily?

A)
B)
C)
D)
E)

Question 9

Which of the following bases most favors elimination over substitution?

A)
B)
C)
D)
E)

Question 10

Which alkyl halide reacts the fastest with sodium methoxide under E2 conditions?

A)
B)
C)
D)
E)

Question 11

In the following reaction, which base most favors the anti-Zaitsev product?

A)
B)
C)
D)
E)