Question 1

Which of the following undergoes the most rapid acylation upon treatment with acetyl chloride and AlCl₃? A) benzene B) toluene C) chlorobenzene D) 1,4-dichlorobenzene

Accepted Answer

Toluene undergoes faster acylation due to the presence of the electron-donating methyl group, which increases the nucleophilicity of the aromatic ring towards the acylating agent. Chlorobenzene and 1,4-dichlorobenzene are deactivated towards electrophilic aromatic substitution due to the presence of electron-withdrawing chlorine atoms. While benzene is more reactive than chlorobenzene and 1,4-dichlorobenzene, it is still less reactive than toluene due to the absence of any electron-donating groups.

Question 2

Which of the following sets of substituents are all ortho/para directing in electrophilic aromatic substitution reactions? A) Cl, CH₃, CN B) Br, OH, COCH₃ C) Cl, OH, CH₃ D) CN, NO₂, COCH₃

Accepted Answer

Cl and CH3 are both electron donating groups, making them ortho/para directing in electrophilic aromatic substitution reactions. OH is also ortho/para directing due to its ability to form hydrogen bonds and stabilize the intermediate.

Question 3

Which of the following undergoes the most rapid sulfonation upon treatment with fuming sulfuric acid?&#10;A) benzene&#10;B) benzoic acid&#10;C) benzonitrile&#10;D) nitrobenzene

Accepted Answer

Benzene undergoes sulfonation more rapidly than the other options because it is less deactivated. Benzoic acid, benzonitrile, and nitrobenzene are more deactivated due to the electron-withdrawing groups, making them less reactive towards electrophilic aromatic substitution reactions like sulfonation.

Question 4

What is the electrophile in the reaction of benzene with tert-butyl chloride and AlCl₃? A) CH₃⁺ B) Cl⁺ C) (CH₃)C⁺ D) benzene

Accepted Answer

In the reaction of benzene with tert-butyl chloride (t-butyl chloride) and AlCl3, the electrophile is the tert-butyl cation, (CH3)3C+. This is formed when AlCl3, a Lewis acid, interacts with tert-butyl chloride, facilitating the departure of the chloride ion and leaving behind the highly reactive tert-butyl cation, which then attacks the benzene ring.

Question 5

Which of the following sets of substituents are all activating groups in electrophilic aromatic substitution reactions? A) Br, NH₂, CH₃ B) CH₃, NH₂, OCH₃ C) OH, COCH_3,CH₃, D) Br, CN, NO₂

Accepted Answer

The substituents CH₃, NH₂, and OCH₃ are all activating groups because they are electron-donating groups that increase the electron density on the aromatic ring, making it more susceptible to nucleophilic attack. Br, CN, and NO₂ are all deactivating groups that withdraw electron density from the ring, making it less reactive towards electrophiles. OH, COCH_{3, and}CH₃ are a mix of activating and deactivating groups and therefore do not all belong to the same category.

Question 6

Which of the following sets of substituents are all meta directing in electrophilic aromatic substitution reactions? A) CN, NO_2,COCH₃ B) CH₃, OCH₃, COCH₃ C) Cl, NH₂, CH₃ D) CH₃, NH₃, OCH₃

Accepted Answer

Meta-directing groups are typically electron-withdrawing groups through resonance or inductive effects. The groups listed in option A (CN, NO2, COCH3) are all known to be electron-withdrawing and thus direct electrophilic substitution to the meta position relative to where they are attached on the benzene ring.

Question 7

Which of the following sets of substituents are all activating groups in electrophilic aromatic substitution reactions? A) CH₃, OCH₃, COCH₃ B) Cl, CN, NO₂ C) Cl, NH₂, CH₃ D) CH₃, NH₂, OCH₃

Accepted Answer

All three substituents in D (CH3, NH2, and OCH3) are activating groups because they donate electrons through resonance to the ring, making it more nucleophilic and thus more susceptible to electrophilic attack. In A, only the OCH3 group is an activating group; the CH3 and COCH3 groups are deactivating. In B, all three substituents are deactivating. In C, the Cl group is deactivating while the NH2 and CH3 groups are activating.

Question 8

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

Accepted Answer

The major product obtained from the given reaction is 2. This is because the reaction involves the oxidation of a primary alcohol with Jones reagent (CrO3/H2SO4) which leads to the formation of a carboxylic acid. In this case, the primary alcohol is octan-1-ol, and the product formed after oxidation is octanoic acid (also known as caprylic acid). The only option that corresponds to octanoic acid is choice B, which shows 2 as the answer.

Question 9

Which of the following sets of substituents are all ortho/para directing in electrophilic aromatic substitution reactions? A) Br, CH₃, NO₂ B) CH₃, NH₂, Br C) Cl, OCH₃, COCH₃ D) NO₂, COCH₃, COOH

Accepted Answer

In general, electron-donating groups are ortho/para directing and electron-withdrawing groups are meta directing in electrophilic aromatic substitution reactions. Choice B contains the electron-donating group NH₂ and two other ortho/para directing groups (CH₃ and Br), making it the best choice. Choices A and C contain both electron-donating and electron-withdrawing groups, while choice D contains only electron-withdrawing groups which are meta directing.

Question 10

Which of the following sets of substituents are all meta directing in electrophilic aromatic substitution reactions? A) CH₃, OH, Br B) Cl, NH₂, CN C) COCH₃, NO_2,COOH D) NH₂, COCH₃, OH

Accepted Answer

Meta-directing groups are typically electron-withdrawing and stabilize the carbocation intermediate less effectively when added to the ortho or para position relative to the substituent. COCH3, NO2, and COOH are all strong electron-withdrawing groups and direct incoming substituents to the meta position in electrophilic aromatic substitution reactions.

Question 11

What is the electrophile in the reaction of benzene with a mixture of nitric acid and sulfuric acid? A) HONO B) NO⁺ C) NO₂⁺ D) benzene

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Question 12

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 13

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 14

What is the role of FeBr₃ in electrophilic aromatic bromination of benzene using Br₂? A) nucleophile B) electrophile C) Lewis acid D) base

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Question 15

What is the electrophile in the reaction of benzene with acetyl chloride, CH₃COCl, and AlCl₃? A) CH₃CºO⁺ B) CH₃⁺ C) CH₃CO₂^- D) benzene

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Question 16

Which of the following undergoes the most rapid bromination upon treatment with Br₂/FeBr₃? A) benzene B) nitrobenzene C) bromobenzene D) anisole

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Question 17

What is the role of AlCl₃ in Friedel Crafts acylations using acid chlorides? A) Lewis acid B) electrophile C) base D) nucleophile

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Question 18

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 19

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 20

Which of the following undergoes the most rapid nitration upon treatment with HNO₃/H₂SO₄? A) toluene B) benzene C) bromobenzene D) nitrobenzene

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Question 21

Which of the following is the structure of the complex of Br₂ with FeBr₃ involved in the electrophilic bromination of benzene? A) 1 B) 2 C) 3 D) 4

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Question 22

Which of the following reactions or reaction sequences will not give isopropylbenzene as the major product? A) treatment of benzene with isopropyl alcohol and HF B) treatment of benzene with 1-chloropropane and AlCl₃ C) treatment of benzene with propanoyl chloride and AlCl₃; followed by reaction with Zn(Hg) and HCl D) treatment of benzene with 1-propene and HF

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Question 23

Which of the following sets of substituents are all deactivating groups in electrophilic aromatic substitution reactions? A) Cl, CN, NO₂ B) Cl, NH₂, CH₃ C) CH₃, OCH₃, COCH₃ D) CH₃, NH₂, OCH₃

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Question 24

Which of the following sets of reagents does not result in alkylation of benzene? A) tert-butyl chloride + AlCl₃ B) tert-butyl alcohol + H₃PO₄ C) methylpropene + HF D) methylpropane + H₂SO₄

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Question 25

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 26

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 27

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 28

Which of the following substituents is ortho/para directing and deactivating in electrophilic aromatic substitution reactions? A) COCH₃ B) NH₃ C) Br D) CH₂CH₃

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Question 29

Which of the following sets of substituents are all deactivating groups in electrophilic aromatic substitution reactions? A) Cl, OH, CH₂CH₃ B) CH₃, Br, COCH₃ C) CH₃, NH₂, OH D) COCH₃, NO₂, Br

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Question 30

Why does anisole undergo bromination with Br₂ in the absence of FeBr₃ whereas bromination of benzene requires the presence of FeBr₃? A) anisole is a better nucleophile than benzene B) the methoxy group of anisole is an inductive electron withdrawing substituent C) Br₂ is a good nucleophile D) the reaction is accelerated by light

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Question 31

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 32

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 33

Why does nitrobenzene fail to undergo Fieldel-Crafts alkylation with tert-butyl chloride and AlCl₃? A) nitrobenzene reacts with AlCl₃ B) nitrobenzene is a poor nucleophile C) the nitro group is a strong electron donating group D) the tert-butyl cation is a poor electrophile

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Question 34

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 35

Which of the following are valid resonance structures of the electophile involved in Friedel-Crafts acylation of benzene upon treatment with CH₃COCl and AlCl₃? A) 1 B) 2 C) 3 D) 4

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Question 36

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 37

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 38

Which of the following substituents is ortho/para directing and deactivating in electrophilic aromatic substitution reactions? A) OH B) Cl C) CH₃ D) NO₂

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Question 39

Which of the following reactions or sequences will provide 1-propylbenzene as the major product? A) treatment of benzene with isopropyl alcohol and HF B) treatment of benzene with propanoyl chloride and AlCl₃; followed by reaction with Zn(Hg) and HCl C) treatment of benzene with 1-chloropropane and AlCl₃ D) treatment of benzene with 1-propene and HF

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Question 40

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 41

Which of the following chlorobenzenes does not undergo nucleophilic aromatic substitution upon treatment with NaNH₂? A) 1 B) 2 C) 3 D) 4

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Question 42

Which mechanism accounts for the reaction of chlorobenzene with acetyl chloride and AlCl₃ to form 4-chloroacetophenone? A) Bimolecular nucleophilic substitution (S_N2) B) Nucleophilic aromatic substitution by elimination-addition C) Nucleophilic aromatic substitution by addition-elimination D) Electrophilic aromatic substitution

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Question 43

Which of the following is the reactive intermediate in the nucleophilic substitution of 4-bromo-1-nitrobenzene with sodium hydroxide?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 44

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 45

Which of the following is the reactive intermediate in the nucleophilic substitution of 4-bromo-1-toluene with sodium amide?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 46

Which of the following compounds undergoes the most rapid nucleophilic substitution with hydroxide ion?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 47

Which of the following is the reactive intermediate formed in the electrophilic Friedel-Crafts acylation of toluene with CH₃COCl and AlCl₃? A) 1 B) 2 C) 3 D) 4

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Question 48

Which of the following cannot be prepared from benzene in two synthetic steps?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 49

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 50

Which mechanism accounts for the reaction of 4-bromo-1-nitrobenzene with sodium hydroxide to form 4-nitrophenol? A) Bimolecular nucleophilic substitution (S_N2) B) Nucleophilic aromatic substitution by elimination-addition C) Nucleophilic aromatic substitution by addition-elimination D) Electrophilic aromatic substitution

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Question 51

Which of the following is the reactive intermediate formed in the electrophilic bromination of toluene with Br₂, FeBr₃? A) 1 B) 2 C) 3 D) 4

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Question 52

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 53

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 54

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 55

Which of the following chlorobenzenes produces a single isomer upon treatment with NaNH₂? A) 1 B) 2 C) 3 D) 4

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Question 56

Which of the following is the reactive intermediate formed in the electrophilic nitration of nitrobenzene with HNO₃ and H₂SO₄? A) 1 B) 2 C) 3 D) 4

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Question 57

What is the major organic product obtained from the following reaction?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 58

What is the major organic product obtained from the following sequence of reactions?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 59

Which of the following compounds undergoes the most rapid nucleophilic substitution with hydroxide ion?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 60

Which of the following cannot be prepared from benzene in two synthetic steps?  &#10;A) 1&#10;B) 2&#10;C) 3&#10;D) 4

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Question 61

Which mechanism accounts for the reaction of 4-bromotoluene with sodium amide to form a mixture of 3- and 4-aminotoluene? A) Bimolecular nucleophilic substitution (S_N2) B) Nucleophilic aromatic substitution by elimination-addition C) Nucleophilic aromatic substitution by addition-elimination D) Electrophilic aromatic substitution

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Question 62

What type of intermediate is formed in the reaction between bromobenzene and sodium amide to give aniline?&#10;A) Meisenheimer complex&#10;B) benzyne&#10;C) cyclohexadienyl cation&#10;D) benzyl radical

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Question 63

Provide the structure (a single resonance contributor) of the key intermediate in the electrophilic aromatic nitration of chlorobenzene.

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Question 64

What is the major organic product obtained from the following reaction?

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Deck 22: Reactions of Benzene and Its Derivatives