Deck 18: Reactions of Benzene and Substituted Benzenes

Question 1

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

Answer 1

An alkene is a better nucleophile than benzene,and thus the Br-Br bond does not have to be weakened to form a better electrophile before reaction.

Question 2

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 2

The addition product is a frequent minor product.

Question 3

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

Answer 3

No,the carbocation is not aromatic since the ring contains an sp³ center.

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

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 6

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

A)HNO₃
B)NO₃
C)NO
D)NO₂
E)NO₂⁺

Question 7

Draw benzyl bromide.

Question 8

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

Question 9

Why does benzene undergo electrophilic substitution rather than electrophilic addition?

Question 10

Name the following compound.

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

Question 11

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 12

Provide the structure of benzenesulfonic acid.

Question 13

Give the best product for the following reaction.

Question 14

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

Question 15

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 16

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

Question 17

What is the structure of styrene?

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

Question 18

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 19

Provide the structure of dibenzyl ether.

Question 20

Provide the structure of anisole.

Question 21

What is the principle of microscopic reversibility?

Question 22

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 23

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

Question 24

Identify the major product for the following reaction.

A)
B)
C)
D)
E)

Question 25

Provide the major organic product of the reaction shown below.

Question 26

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

A)
B)
C)
D)
E)AlCl₃

Question 27

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 28

Predict the major organic product of the following reaction.

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

Question 29

Provide the major organic product of the reaction shown below.

Question 30

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 31

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 32

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

Question 33

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 34

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

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

Question 35

Provide the major organic product of the reaction shown below.

Question 36

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

Question 37

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 38

Provide the major organic product of the following.

Question 39

Provide the major organic product of the reaction shown below.

Question 40

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 41

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

Question 42

What is the major product of the following reaction?

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

Question 43

Provide the major organic product of the following.

Question 44

Identify the best product for the following reaction.

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

Question 45

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 46

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

A)ethylbenzene
B)1-propylbenzene
C)butylbenzene
D)sec-butylbenzene
E)isobutylbenzene

Question 47

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 48

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

Question 49

What is the major product of the following reaction?

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

Question 50

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

Question 51

Identify the condition(s)that will not work for the following reaction.You may choose more than one answer.

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

Question 52

Identify the reaction(s)below that give benzoic acid as a product.You may choose more than one answer.

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 53

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 54

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 55

Give the organic products from the following reaction.

Question 56

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

Question 57

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

Question 58

Identify the product(s)for the following reaction.

A)
B)
C)
D)
E)

Question 59

What is the major product of the following reaction?

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

Question 60

Give the organic products from the following reaction.

Question 61

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 62

Provide the best name for the organic compound below.

Question 63

Identify the best product for the following reaction.

A)
B)
C)
D)
E)

Question 64

Provide the structure of benzoic acid.

Question 65

Name the following structure.

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

Question 66

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 67

Give the best product for the following reaction.

Question 68

Provide the best name for the organic compound below.

Question 69

What is the structure of phenol?

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

Question 70

What is the structure of 3-phenylpentane?

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

Question 71

Give three different correct names for the structure.

Question 72

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 73

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 74

Provide the structure of anisole.

Question 75

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 76

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 77

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 78

What is the structure of p-toluidine?

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

Question 79

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

Question 80

Give the best product for the following reaction.