Deck 19: Reactions of Benzene and Substituted Benzenes

Question 1

Which of the following is most likely to be the first step in the general mechanism for electrophilic substitution reactions?

A)I
B)II
C)III
D)IV
E)V

Answer 1

II

Question 2

Why does benzene undergo electrophilic substitution rather than electrophilic addition?

Answer 2

When benzene undergoes electrophilic substitution, the product retains the stability associated with an aromatic system. This stability is lost in electrophilic addition because the product is not aromatic.

Question 3

Which of the following is not a correct statement about the electrophilic substitution mechanism of benzene?

A)Benzene functions as a nucleophile.
B)Formation of a carbocation intermediate is the rate-determining step.
C)The carbocation intermediate contains an sp³ hybridized carbon in the ring.
D)The addition product is a frequent minor product.
E)Aromaticity is regained by loss of H⁺.

Answer 3

The addition product is a frequent minor product.

Question 4

Which of the following is the first step in the mechanism of bromination?

A)I
B)II
C)III
D)IV
E)V

Question 5

In the bromination of benzene using Br₂ and FeBr₃, is the intermediate carbocation aromatic? Explain.

Question 6

Which step in the general mechanism for electrophilic aromatic substitution is rate-determining? Explain.

Question 7

Provide a detailed, stepwise mechanism for the reaction of benzene with Br₂ and FeBr₃. Make sure to include the activating reaction between Br₂ and FeBr₃ in your mechanism.

Question 8

What purpose does FeCl₃ serve in the electrophilic aromatic substitution reaction between chlorine and benzene?

A)It serves as a radical initiator to produce the chlorine radical needed to propagate the chain reaction.
B)It functions by destabilizing the carbocationic intermediate and thereby increases the rate of H⁺ loss.
C)It serves as a Lewis base catalyst by reacting with Cl₂ to generate chloride ions.
D)It functions by destabilizing the benzene through formation of a π-complex.
E)It serves as a Lewis acid catalyst by reacting with the Cl₂ and thereby activates it toward attack by benzene's π electrons.

Question 9

What specific electrophile is attacked by benzene when it undergoes nitration?

A)HNO₃
B)NO₃
C)NO
D)NO₂
E)NO₂⁺

Question 10

Bromination of benzene requires a Lewis acid catalyst while bromination of cyclohexene does not. Explain this difference in reactivity.

Question 11

Give the best product for the following reaction.

Question 12

Which of the following is the electrophile that attacks the aromatic ring during nitration?

A)NO₂
B)HNO₃
C)HNO₃^-
D)NO₂⁺
E)NO₂^-

Question 13

Draw benzyl bromide.

Question 14

Provide the structure of anisole.

Question 15

Provide the structure of dibenzyl ether.

Question 16

Which of the following is one of the resonance contributors of the intermediate produced in a Friedel-Crafts alkylation of benzene?

A)I
B)II
C)III
D)IV
E)V

Question 17

Provide the structure of benzenesulfonic acid.

Question 18

What is the structure of styrene?

A)I
B)II
C)III
D)IV
E)V

Question 19

Provide the major resonance structures of the intermediate sigma complex in the reaction of benzene with the generic electrophile E⁺.

Question 20

Name the following compound.

A)sec-hexylbenzene
B)3-phenylhexane
C)2-phenylhexane
D)tert-hexylbenzene
E)isohexylbenzene

Question 21

Which of the following is not a correct statement concerning the Friedel-Crafts acylation of benzene?

A)An alkyl group substitutes for a hydrogen.
B)The benzene ring attacks an acylium ion.
C)The acylium ion is resonance stabilized.
D)The acylium ion is often produced from an acyl chloride.
E)More than one equivalent of Lewis acid must be used.

Question 22

Provide the major organic product of the reaction shown below.

Question 23

Which of the following is the electrophile that attacks the aromatic ring during Friedel-Crafts acylation?

A)
B)
C)
D)
E)AlCl₃

Question 24

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 25

Provide the major organic product of the reaction shown below.

Question 26

Why must Friedel-Crafts acylation reactions be run with more than a single equivalent of AlCl₃?

Question 27

Provide the major organic product of the reaction shown below.

Question 28

Name the major organic product which results when 4-ethylbenzenesulfonic acid is heated in aqueous acid.

Question 29

What is the major organic product of the reaction between benzene and isobutyl chloride in the presence of AlCl₃?

A)tert-butylbenzene
B)isobutylbenzene
C)n-butylbenzene
D)chlorobenzene
E)sec-butylbenzene

Question 30

What is the principle of microscopic reversibility?

Question 31

Identify the major product for the following reaction.

A)
B)
C)
D)
E)

Question 32

Provide the major organic product of the following.

Question 33

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 34

Predict the major organic product of the following reaction.

A)I
B)II
C)III
D)IV
E)V

Question 35

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 36

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 37

What is the major product of the following Friedel-Crafts alkylation?

A)I
B)II
C)III
D)IV
E)V

Question 38

Provide the major organic product of the reaction shown below.

Question 39

Which of the following is the electrophile that attacks the aromatic ring during sulfonation?

A)HSO₃⁺
B)SO₂⁺
C)HSO₃^-
D)H₂SO₄
E)HSO₄^-

Question 40

Provide the structure of the major organic product of the following reaction.

Question 41

Provide the major organic product of the following.

Question 42

Give the organic products from the following reaction.

Question 43

What is the major organic product of the reaction shown below?

Question 44

What is the major organic product that results when benzene is treated with 1-chlorobutane and AlCl₃?

A)ethylbenzene
B)isobutylbenzene
C)butylbenzene
D)sec-butylbenzene

Question 45

Give the organic products from the following reaction.

Question 46

What is the major product of the following reaction?

A)I
B)II
C)III
D)IV
E)V

Question 47

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 48

Identify the reaction(s)below that give benzoic acid as a product.

A)1-phenylethanol + manganese dioxide + heat
B)1-phenylethanol + sodium dichromate + acid + heat
C)tert-butylbenzene + sodium dichromate + acid + heat
D)ethylbenzene + sodium dichromate + acid + heat
E)phenylmethanol + manganese dioxide + heat

Question 49

Benzene can be reduced to cyclohexane when it is treated with hydrogen in the presence of a nickel catalyst under conditions of high temperature and pressure. Predict the signs of ΔH° and ΔS° for this process.

A)ΔH° > 0, ΔS° > 0
B)ΔH° > 0, ΔS° < 0
C)ΔH° > 0, ΔS° = 0
D)ΔH° < 0, ΔS° > 0
E)ΔH° < 0, ΔS° < 0

Question 50

Identify the best product for the following reaction.

A) + LiBr
B)
C)
D)
E)

Question 51

What is the major product of the following reaction?

A)I
B)II
C)III
D)IV
E)V

Question 52

What is the major organic product of the reaction shown below?

Question 53

Identify the condition(s)that will not work for the following reaction.

A)
B)
C)
D)CH₃CH₂CH₂Cl + AlCl₃
E)CH₃CH₂CH₂OH, H₂SO₄

Question 54

What is the major product of the following reaction?

A)I
B)II
C)III
D)IV
E)V

Question 55

Which of the following fails to produce benzoic acid when heated in the presence of acidic sodium dichromate?

A)1-phenylethanol
B)2-phenylethanol
C)2-phenylheptane
D)2-methyl-2-phenylheptane
E)1-phenylheptanol

Question 56

What is the major organic product of the reaction shown below?

Question 57

Provide the structure of the major organic product of the following reaction sequence.

Question 58

Provide the structure of the major organic product of the following reaction.

Question 59

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 60

Identify the product(s)for the following reaction.

A)
B)
C)
D)
E)

Question 61

Give the best product for the following reaction.

Question 62

What is the structure of 3-phenylpentane?

A)I
B)II
C)III
D)IV
E)V

Question 63

Give the best name for the structure.

A)2-methyl-1,3,5-trinitrobenzene
B)1,3,5-triaminotoluene
C)1,3,5-trinitrotoluene
D)2,4,6-triaminotoluene
E)2,4,6-trinitrotoluene

Question 64

Provide the best name for the organic compound below.

Question 65

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 66

Give the best product for the following reaction.

Question 67

What is the name of the following compound?

A)m-bromomethylbenzene
B)m-bromotoluene
C)3-bromotoluene
D)A and B
E)B and C

Question 68

Provide the structure of benzoic acid.

Question 69

Can one distinguish among the three isomeric xylenes using ¹³C NMR? Explain.

Question 70

How many signals does one expect in the proton decoupled ¹³C NMR spectrum of o-xylene?

A)8
B)6
C)4
D)3
E)2

Question 71

Name the following structure.

A)2-chlorobenzoic acid
B)3-chlorobenzoic acid
C)2-chlorobenzaldehyde
D)3-chlorobenzaldehyde
E)3-chloroacetophenone

Question 72

What is the name of the following compound?

A)o-nitro-m-bromotoluene
B)3-bromo-6-nitrotoluene
C)m-bromo-o-nitrotoluene
D)5-bromo-2-nitrotoluene
E)2-nitro-5-bromotoluene

Question 73

Give three different correct names for the structure.

Question 74

What is the proper name of the compound below?

A)1-phenoxyethane
B)ethyl phenyl ether
C)m-butylhydroxybenzene
D)o-butylhydroxybenzene
E)m-butylphenol

Question 75

The name 2,4,6-tribromobenzene is incorrect. Which of the following is the correct name?

A)tribromobenzene
B)m,m-dibromobromobenzene
C)3,5-dibromobromobenzene
D)1,3,5-tribromobenzene
E)m,m,m-tribromobenzene

Question 76

What is the structure of phenol?

A)I
B)II
C)III
D)IV
E)V

Question 77

Provide the best name for the organic compound below.

Question 78

What is the name of the following compound?

A)p-dichlorobenzene
B)1,4-dichlorobenzene
C)phenyldichloride
D)A and B
E)B and C

Question 79

Provide the structure of anisole.

Question 80

What is the structure of p-toluidine?

A)I
B)II
C)III
D)IV
E)V