ORGANIC CHEMISTRY II FINAL EXAM ||quESTIONS ANd ANSwERS wITH
RATIONALES/GRAdEd A+/2026 updATE/100% CORRECT /INSTANT
dOwNLOAd
SECTION 1: AROMATIC COMPOUNDS (Questions 1-15)
Question 1
Which of the following compounds is aromatic according to Hückel's rule?
A) Cyclobutadiene
B) Benzene
C) Cyclooctatetraene
D) Cyclopropene
Correct Answer: B
Rationale: Hückel's rule states that a planar, cyclic, fully conjugated system is aromatic
if it has (4n+2) π electrons. Benzene has 6 π electrons (n=1). Cyclobutadiene has 4 π
electrons (antiaromatic). Cyclooctatetraene is nonplanar and nonaromatic. Cyclopropene
is not fully conjugated.
Question 2
What is the major product of the nitration of toluene?
A) o-Nitrotoluene only
B) m-Nitrotoluene only
C) p-Nitrotoluene only
D) A mixture of o-nitrotoluene and p-nitrotoluene
Correct Answer: D
,Rationale: The methyl group in toluene is an ortho/para director. Nitration yields a
mixture of ortho and para products, with the para isomer typically predominating due to
steric effects.
Question 3
Which substituent is a meta director in electrophilic aromatic substitution?
A) -OH
B) -CH₃
C) -NO₂
D) -OCH₃
Correct Answer: C
Rationale: The nitro group (-NO₂) is a strong electron-withdrawing group that directs
incoming electrophiles to the meta position. -OH, -CH₃, and -OCH₃ are ortho/para
directors.
Question 4
What is the product of the Friedel-Crafts alkylation of benzene with 2-chloropropane and
AlCl₃?
A) Propylbenzene (straight chain)
B) Isopropylbenzene (cumene)
C) n-Propylbenzene
D) Benzene (no reaction)
Correct Answer: B
,Rationale: Friedel-Crafts alkylation with 2-chloropropane leads to carbocation
rearrangement. The secondary isopropyl carbocation forms and attacks benzene to give
isopropylbenzene (cumene). No straight-chain product is formed.
Question 5
What is the product of the Friedel-Crafts acylation of benzene with acetyl chloride
(CH₃COCl) and AlCl₃?
A) Ethylbenzene
B) Acetophenone (C₆H₅COCH₃)
C) Benzaldehyde
D) Benzoic acid
Correct Answer: B
Rationale: Friedel-Crafts acylation introduces an acyl group (COCH₃) onto the benzene
ring, forming acetophenone. Unlike alkylation, acylation does not undergo
rearrangements.
Question 6
Why does Friedel-Crafts alkylation often give polyalkylated products while acylation
does not?
A) Alkyl groups are activating; acyl groups are deactivating
B) Acyl groups are activating; alkyl groups are deactivating
C) Alkyl halides are more reactive than acyl halides
D) Acylation requires higher temperatures
Correct Answer: A
, Rationale: Alkyl groups are activating toward electrophilic aromatic substitution, so the
monoalkylated product is more reactive than benzene, leading to polyalkylation. Acyl
groups are deactivating, preventing further substitution.
Question 7
What is the product of the sulfonation of nitrobenzene?
A) o-Nitrobenzenesulfonic acid
B) m-Nitrobenzenesulfonic acid
C) p-Nitrobenzenesulfonic acid
D) Benzenesulfonic acid
Correct Answer: B
Rationale: The nitro group is a meta director. Therefore, sulfonation of nitrobenzene
occurs primarily at the meta position, yielding m-nitrobenzenesulfonic acid.
Question 8
Which of the following halobenzenes is most reactive in electrophilic aromatic
substitution?
A) Fluorobenzene
B) Chlorobenzene
C) Bromobenzene
D) Iodobenzene
Correct Answer: A
Rationale: Halogens are ortho/para directors but deactivating overall. Among halogens,
fluorine is the least deactivating because of its strong electron-donating resonance
effect. Reactivity order in EAS: F > Cl > Br > I.
RATIONALES/GRAdEd A+/2026 updATE/100% CORRECT /INSTANT
dOwNLOAd
SECTION 1: AROMATIC COMPOUNDS (Questions 1-15)
Question 1
Which of the following compounds is aromatic according to Hückel's rule?
A) Cyclobutadiene
B) Benzene
C) Cyclooctatetraene
D) Cyclopropene
Correct Answer: B
Rationale: Hückel's rule states that a planar, cyclic, fully conjugated system is aromatic
if it has (4n+2) π electrons. Benzene has 6 π electrons (n=1). Cyclobutadiene has 4 π
electrons (antiaromatic). Cyclooctatetraene is nonplanar and nonaromatic. Cyclopropene
is not fully conjugated.
Question 2
What is the major product of the nitration of toluene?
A) o-Nitrotoluene only
B) m-Nitrotoluene only
C) p-Nitrotoluene only
D) A mixture of o-nitrotoluene and p-nitrotoluene
Correct Answer: D
,Rationale: The methyl group in toluene is an ortho/para director. Nitration yields a
mixture of ortho and para products, with the para isomer typically predominating due to
steric effects.
Question 3
Which substituent is a meta director in electrophilic aromatic substitution?
A) -OH
B) -CH₃
C) -NO₂
D) -OCH₃
Correct Answer: C
Rationale: The nitro group (-NO₂) is a strong electron-withdrawing group that directs
incoming electrophiles to the meta position. -OH, -CH₃, and -OCH₃ are ortho/para
directors.
Question 4
What is the product of the Friedel-Crafts alkylation of benzene with 2-chloropropane and
AlCl₃?
A) Propylbenzene (straight chain)
B) Isopropylbenzene (cumene)
C) n-Propylbenzene
D) Benzene (no reaction)
Correct Answer: B
,Rationale: Friedel-Crafts alkylation with 2-chloropropane leads to carbocation
rearrangement. The secondary isopropyl carbocation forms and attacks benzene to give
isopropylbenzene (cumene). No straight-chain product is formed.
Question 5
What is the product of the Friedel-Crafts acylation of benzene with acetyl chloride
(CH₃COCl) and AlCl₃?
A) Ethylbenzene
B) Acetophenone (C₆H₅COCH₃)
C) Benzaldehyde
D) Benzoic acid
Correct Answer: B
Rationale: Friedel-Crafts acylation introduces an acyl group (COCH₃) onto the benzene
ring, forming acetophenone. Unlike alkylation, acylation does not undergo
rearrangements.
Question 6
Why does Friedel-Crafts alkylation often give polyalkylated products while acylation
does not?
A) Alkyl groups are activating; acyl groups are deactivating
B) Acyl groups are activating; alkyl groups are deactivating
C) Alkyl halides are more reactive than acyl halides
D) Acylation requires higher temperatures
Correct Answer: A
, Rationale: Alkyl groups are activating toward electrophilic aromatic substitution, so the
monoalkylated product is more reactive than benzene, leading to polyalkylation. Acyl
groups are deactivating, preventing further substitution.
Question 7
What is the product of the sulfonation of nitrobenzene?
A) o-Nitrobenzenesulfonic acid
B) m-Nitrobenzenesulfonic acid
C) p-Nitrobenzenesulfonic acid
D) Benzenesulfonic acid
Correct Answer: B
Rationale: The nitro group is a meta director. Therefore, sulfonation of nitrobenzene
occurs primarily at the meta position, yielding m-nitrobenzenesulfonic acid.
Question 8
Which of the following halobenzenes is most reactive in electrophilic aromatic
substitution?
A) Fluorobenzene
B) Chlorobenzene
C) Bromobenzene
D) Iodobenzene
Correct Answer: A
Rationale: Halogens are ortho/para directors but deactivating overall. Among halogens,
fluorine is the least deactivating because of its strong electron-donating resonance
effect. Reactivity order in EAS: F > Cl > Br > I.
