Deck 19: Reactions of Aromatic Compounds

Question 1

What is the major product of the following reaction?

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

Answer 1

IV

Question 2

How can polyalkylation be minimized in Friedel-Crafts alkylation?

A) Use an alkyl halide without a Lewis acid catalyst.
B) Use a large excess of the Lewis acid catalyst.
C) Use a large excess of alkyl halide relative to the aromatic compound.
D) Use a large excess of benzene relative to the alkyl halide.

Answer 2

Use a large excess of benzene relative to the alkyl halide.

Question 3

Which of the following statements about nucleophilic aromatic substitution isnot true?

A) Electron-withdrawing groups stabilize the intermediate carbanion, and lower the energy of the transition state.
B) When a nitro group is located meta to the halogen, the negative charge of the intermediate carbanion can be delocalized onto the NO₂ group, thus stabilizing it.
C) Increasing the number of electron-withdrawing groups increases the reactivity of the aryl halide.
D) Increasing the electronegativity of the halogen increases the reactivity of the aryl halide.

Answer 3

When a nitro group is located meta to the halogen, the negative charge of the intermediate carbanion can be delocalized onto the NO₂ group, thus stabilizing it.

Question 4

What is the product of the following reaction?

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

Question 5

What is the major product of the following reaction?

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

Question 6

What is the product of the following reaction?

A) I
B) None of these
C) III
D) II

Question 7

Why is the nitro group ameta director?

A) Because it is sterically very large
B) Because it removes more electron density from theortho andpara positions than themeta position, thus deactivating themeta position less
C) Because it adds electron density to themeta position, thus activating it
D) Because it stabilizes the intermediate cation

Question 8

What reagents would be necessary to produce the following product from benzene?

A) KMnO₄ 2. HNO₃, H₂SO₄ 3.CH₃Cl, AlCl₃
B) CH₃Cl, AlCl₃ 2. HNO₃, H₂SO₄ 3. KMnO₄
C) HNO₃, H₂SO₄ 2. CH₃Cl, AlCl₃ 3. KMnO₄
D) KMnO₄ 2. CH₃Cl, AlCl₃ 3. HNO₃, H₂SO₄

Question 9

What is a major problem with Friedel-Crafts alkylation?

A) The products coordinate with the aluminum chloride.
B) The starting material is frequently over-alkylated.
C) It requires high temperatures.
D) The conditions are too acidic.

Question 10

What reagents would be necessary to produce the following product from benzene?

A) Zn(Hg), HCl 2. CH₃CH₂C(O)Cl, AlCl₃ 3. HNO₃, H₂SO₄
B) CH₃CH₂C(O)Cl, AlCl₃ 2. Zn(Hg), HCl 3. HNO₃, H₂SO₄
C) CH₃CH₂C(O)Cl, AlCl₃ 2. HNO₃, H₂SO₄ 3. Zn(Hg), HCl
D) HNO₃, H₂SO₄ 2. CH₃CH₂C(O)Cl, AlCl₃ 3. Zn(Hg), HCl

Question 11

Which of the following statements about nucleophilic aromatic substitution is true?

A) For the elimination-addition pathway, the nucleophile becomes attached only at the site bearing the leaving group.
B) For the addition-elimination pathway, the nucleophile may become attached either at the site bearing the leaving group or at the site bearing the ortho hydrogen atom.
C) The elimination-addition mechanism is not as common as the addition-elimination mechanism.
D) In the addition-elimination mechanism, the aromatic ring first accepts a pair of electrons from a nucleophile to form a cationic intermediate.

Question 12

What is the product of the following reaction?

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