Deck 22: Chemistry of the Benzene Substituents: Alkylbenzenes,phenols,and Benzenamines

Question 1

Why does the substitution of ortho or para nitro groups onto chlorobenzene greatly increase the tendency of the chlorine to be displaced by nucleophiles?

A) NO₂ groups stabilize the S_N1 transition state by resonance.
B) The NO₂ groups facilitate removal of a hydrogen $\alpha$ to chlorine.
C) NO₂ groups stabilize the S_N2 transition state.
D) NO₂ groups stabilize negative charge resulting from addition of a nucleophile.
E) The NO₂ groups exert a general inductive effect which is independent of substitution position.

Answer 1

NO₂ groups stabilize negative charge resulting from addition of a nucleophile.

Question 2

Which of the following resonance structures of the phenoxide anion would be the major contributor to the real structure?

A)

B)

C)

D)

E) All are equally important.

Answer 2

Question 3

What product would you expect from the following reaction?

A)

B)

C)

D)

E)

Answer 3

Question 4

How would you rank the following in decreasing order of reactivity toward nucleophilic aromatic substitution (most reactive on left)?

A) 4 > 1 > 3 > 2
B) 2 > 3 > 1 > 4
C) 3 > 2 > 4 > 1
D) 1 > 3 > 2 > 4
E) impossible to predict

Question 5

By which of the following can the N₂ group of a benzenediazonium salt not be substituted?

A) CN
B) CH₃
C) H
D) F
E) OH

Question 6

What major product would you expect from the following reaction?

A)

B)

C)

D)

E) both A and D

Question 7

What would be the expected product of the following reaction?

A)

B)

C)

D)

E)

Question 8

What would be the result of the following?

A)

B)

C)

D)

E) no reaction

Question 9

What material is produced easily by means of the Kolbe reaction? (sodium phenoxide + CO₂ + heat/pressure,then H₃O⁺)

A) Phenol
B) Benzaldehyde
C) Succinic acid
D) Cinnamic acid
E) Salicylic acid

Question 10

What would be the proper ranking of the following in order of decreasing acidity (most acidic on left)?

A) 4 > 2 > 1 > 3
B) 3 > 1 > 4 > 2
C) 2 > 4 > 1 > 3
D) 3 > 2 > 4 > 1
E) 2 > 4 > 3 > 1

Question 11

Which of the following is not a valid resonance contributor to the benzyl radical?

A)

B)

C)

D)

E)

Question 12

To which side (if any)would the following equilibrium lie?

A) To the left
B) To the right
C) Equally to the left and right
D) Reaction cannot occur at all
E) Equilibrium favors a different product

Question 13

What would be the proper ranking of the following in order of decreasing acidity (most acidic on left)?

A) A > B > C
B) B > C > A
C) A > C > B
D) B > A > C
E) C > B > A

Question 14

What happens when a secondary amine is treated with nitrous acid?

A) A diazonium salt is formed.
B) It immediately loses nitrogen to form a carbocation.
C) A simple acid-base reaction occurs to give an alkyl ammonium nitrite salt.
D) An N-nitroso amine is formed.
E) A dealkylation occurs to give a primary amine.

Question 15

What would be the expected product of the following reaction?

A)

B)

C)

D)

E) both A and D

Question 16

What is the main use of azo compounds in general?

A) Antibiotic properties
B) Fragrances and flavorings
C) Chemotherapy agents
D) Herbicides and/or pesticides
E) Dyes and coloring agents

Question 17

What would be the expected product(s)from the following reaction?

A)

B)

C)

D) both A and B
E) All of the above.

Question 18

Which ion would be most stabilized by resonance?

A)

B)

C)

D)

E) All are equally stabilized.

Question 19

From what starting materials would the following be made?

A)

B)

C) Either A or B
D) Neither A nor B
E) The compound shown is too unstable to isolate.

Question 20

What product would result from the following reaction?

A)

B)

C)

D)

E) None of these.

Question 21

Which of the following is not a valid resonance contributor in the benzenediazonium cation?

A)

B)

C)

D)

E) All of the above are valid resonance structures.

Question 22

Predict the major product of the following solvolysis reaction:

A)

B)

C)

D)

E) None of the above.

Question 23

When considering the mechanism of the reaction shown below,which of the following is most likely an intermediate along the reaction pathway?

A)

B)

C)

D)

E)

Question 24

Considering the mechanism for the following reaction,which of the following is most likely the rate determining step (RDS)?

A)

B)

C)

D)

E)

Question 25

Arrange the following structures according to decreasing acidity?

A) 1 > 3 > 4 > 2
B) 2 > 4 > 3 > 1
C) 4 > 3 > 1 > 2
D) 3 > 2 > 1 > 4
E) 4 > 1 > 3 > 2

Question 26

The following reaction most likely proceeds by what mechanism:

A) S_N2
B) S_N1
C) E2
D) E1
E) Free radical halogenation

Question 27

Which of the following is not a valid resonance contributor in the benzylic anion?

A)

B)

C)

D)

E) All of these are valid resonance structures.

Question 28

Starting with the labeled chlorobenzene (label indicated by *),what is the product of the following nucleophilic aromatic substitution reaction?

A)

B)

C)

D)

E) structures B and C

Question 29

Which of the following represents a hydrogenolysis reaction?

A)

B)

C)

D)

E) Two or more of these are correct.

Question 30

Predict the major product of the following Sandmeyer reaction:

A)

B)

C)

D)

E)

Question 31

Predict the major product of the following reaction:

A)

B)

C)

D)

E)

Question 32

Which of the reagents given below would accomplish the reaction shown?

A) H₂O₂,KOH,heat
B) Na₂Cr₂O₇,H⁺,heat
C) ClCO₂H,AlCl₃
D) O₃,then H₂O
E) None of these.