Question 1

Which of the following reactions of benzene does not proceed by electrophilic aromatic substitution?&#10;A) halogenation&#10;B) nitration&#10;C) sulfonation&#10;D) Friedel-Crafts alkylation and acylation&#10;E) All of these are electrophilic aromatic substitution reactions.

Accepted Answer

All of these reactions proceed by the same mechanism (electrophilic addition to a benzene ring, followed by loss of a proton).

Question 2

Which of the following statements is not true about the sulfonation of benzene?&#10;A) Heating sulfuric acid leads to formation of the + SO 3 H electrophile.&#10;B) Sulfonation is irreversible.&#10;C) Sulfonation occurs through an electrophilic aromatic substitution mechanism.&#10;D) The rate limiting step is formation of a resonance stabilized carbocation intermediate.&#10;E) All of these statements are true.

Accepted Answer

Sulfonic acids are desulfonated by heating in dilute acid.

Question 3

Which set of reagents should be used to prepare n-propylbenzene?  &#10;A) benzene, CH 3 CH 2 CH 2 Cl, AlCl 3 &#10;B) benzene, CH 3 CH?CH 2 , HF&#10;C) benzene,1.CH 3 CH 2 COCl/AlCl 3 2.H 2 O 3.NH 2 NH 2 /HO - /?&#10;D) benzene, CH 3 CH 2 CH 2 OH, H 2 SO 4 &#10;E) chlorobenzene, CH 3 CH?CH 2 , AlCl 3

Accepted Answer

benzene,1.CH 3 CH 2 COCl/AlCl 3 2.H 2 O 3.NH 2 NH 2 /HO - /?&#10;

Question 4

Which is the preferred method for the synthesis of biphenyl?  &#10;A) a Gilman reaction&#10;B) a Heck reaction&#10;C) a Friedel-Crafts acylation reaction&#10;D) a Suzuki reaction&#10;E) all of the above

Accepted Answer

A Suzuki coupling reaction is commonly employed to form biaryl molecules.

Question 5

Which set of reagents should be used to prepare benzaldehyde?  &#10;A) toluene, 1. H 2 CrO 4 2. LiAlH 4 3. H 2 O&#10;B) toluene, 1. H 2 CrO 4 2. NaBH 4 3. H 2 O&#10;C) toluene, 1. H 2 CrO 4 2. NaBH 4 3. PCC&#10;D) toluene, 1. H 2 CrO 4 2. LiAlH 4 3. PCC&#10;E) toluene, PCC

Accepted Answer

Oxidation to form the acid followed by reduction to form the alcohol and PCC oxidation to form the aldehyde will give the product.

Question 6

What is the name of the compound shown here?  &#10;A) 1-fluoro-3-methyl-6-nitrobenzene&#10;B) 3-fluoro-4-nitro-1-methylbenzene&#10;C) 3-fluoro-1-methyl-1-nitrobenzene&#10;D) 2-fluoro-1-nitro-4-methylbenzene&#10;E) 2-fluoro-4-methyl-1-nitrobenzene

Accepted Answer

List the substituents in alphabetical order and then number so that the lowest numbers are in the name.

Question 7

Which of the following activates a benzene ring toward electrophilic aromatic substitution?&#10;A)  &#10;B)  &#10;C)  &#10;D)  &#10;E)

Accepted Answer

Except for the halogens, a group with a lone pair on the atom attached to the benzene ring is an activator

Question 8

Which of the following is an ortho-para director?&#10;A) ?Cl&#10;B) ?CHO&#10;C) ?CN&#10;D) ?NO 2 &#10;E) none of the above

Accepted Answer

Although ?Cl is a deactivator, its lone pair stabilizes the carbocation intermediate when the incoming substituent is ortho or para.

Question 9

Which compound is the major product of the following reaction?&#10; &#10;A)  &#10;B)  &#10;C)  &#10;D)  &#10;E)

Accepted Answer

The answer of Which compound is the major product of...

Question 10

Which of the following groups most strongly activates an aromatic ring toward Friedel-Crafts acylation?&#10;A) ?NH 2 &#10;B) ?OCH 3 &#10;C) ?O-C(?O)CH 3 &#10;D) NO 2 &#10;E) H

Accepted Answer

Although the ?NHS1U1B12S1U1B0 group is a strong activator, it complexes with AlClS1U1B13S1U1B0 to form a strongly deactivating ammonium group. Consequently, the methoxy is the best activator.

Question 11

Which of the following series of reactions will give the desired product?&#10; &#10;A)  &#10;B)  &#10;C)  &#10;D)  &#10;E)

Accepted Answer

The answer of Which of the following series of reactions...

Deck 18: Reactions of Benzene and Substituted Benzenes