,Verified CHEM 219 Module 2 Exam Principles of
Organic Chemistry w/Lab | Portage (2026–2027)
Actual(PDF)
1. What is the correct IUPAC name for the compound CH₃-CH₂-CH(CH₃)-CH₂-CH₂-CH₃?
A) 2-methylhexane
B) 3-methylhexane
C) 2-methylpentane
D) 3-methylpentane
Correct Answer: 3-methylhexane
Rationale: The longest continuous carbon chain contains six carbons, making the parent alkane
hexane. Numbering from either end gives the methyl substituent at position 3. Therefore, the correct
IUPAC name is 3-methylhexane. "2-methylhexane" would result from incorrect numbering, while the
other options are based on incorrect parent chain lengths.
2. Which of the following functional groups has the highest priority for IUPAC nomenclature?
A) Alcohol
B) Aldehyde
C) Carboxylic acid
D) Ketone
Correct Answer: Carboxylic acid
Rationale: In IUPAC nomenclature, functional groups are assigned a priority order for choosing the
parent chain and suffix. Carboxylic acids have the highest priority among the common functional
groups, followed by esters, amides, nitriles, aldehydes, ketones, alcohols, and amines. Therefore, a
carboxylic acid will always be the principal functional group.
,3. A molecule is classified as being both aliphatic and heterocyclic. Which of the following structures
fits this description?
A) Benzene
B) Cyclohexane
C) Tetrahydrofuran
D) Pyridine
Correct Answer: Tetrahydrofuran
Rationale: Aliphatic compounds are non-aromatic, and heterocyclic compounds contain a ring with at
least one atom other than carbon. Tetrahydrofuran is a saturated, non-aromatic ring containing an
oxygen atom, fitting both descriptions. Benzene and pyridine are aromatic, and cyclohexane is
carbocyclic (contains only carbon).
4. What is the relationship between the two compounds shown below?
CH₃-CH₂-CH₂-CH₃ and CH₃-CH(CH₃)-CH₃
A) They are the same compound.
B) They are constitutional isomers.
C) They are stereoisomers.
D) They are different compounds with different molecular formulas.
Correct Answer: They are constitutional isomers.
Rationale: Both compounds have the molecular formula C₄H₁₀. The first is the straight-chain butane,
and the second is the branched isobutane (2-methylpropane). They differ in the connectivity of their
atoms, which defines them as constitutional (structural) isomers.
5. Which of the following is the correct structure for 2,2-dimethylbutane?
A) CH₃-C(CH₃)₂-CH₂-CH₃
B) CH₃-CH(CH₃)-CH₂-CH₂-CH₃
C) CH₃-C(CH₃)₂-CH₃
, D) CH₃-CH₂-C(CH₃)₂-CH₂-CH₃
Correct Answer: CH₃-C(CH₃)₂-CH₂-CH₃
Rationale: The parent chain is butane (four carbons). Two methyl groups are attached to the second
carbon. This structure is represented as CH₃-C(CH₃)₂-CH₂-CH₃. The other options have incorrect parent
chain lengths or incorrect placement of substituents.
6. Which of the following statements about the combustion of alkanes is true?
A) Complete combustion of an alkane produces carbon monoxide and water.
B) Complete combustion of an alkane produces carbon dioxide and water.
C) Incomplete combustion of an alkane produces only carbon dioxide.
D) Alkanes do not undergo combustion reactions.
Correct Answer: Complete combustion of an alkane produces carbon dioxide and water.
Rationale: Complete combustion of a hydrocarbon, such as an alkane, in the presence of sufficient
oxygen produces carbon dioxide (CO₂) and water (H₂O). Incomplete combustion produces carbon
monoxide (CO) and/or carbon (soot) along with water.
7. What is the IUPAC name for the following compound?
CH₃-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH₃
A) Octane
B) Octene
C) Octyne
D) Cyclooctane
Correct Answer: Octane
Organic Chemistry w/Lab | Portage (2026–2027)
Actual(PDF)
1. What is the correct IUPAC name for the compound CH₃-CH₂-CH(CH₃)-CH₂-CH₂-CH₃?
A) 2-methylhexane
B) 3-methylhexane
C) 2-methylpentane
D) 3-methylpentane
Correct Answer: 3-methylhexane
Rationale: The longest continuous carbon chain contains six carbons, making the parent alkane
hexane. Numbering from either end gives the methyl substituent at position 3. Therefore, the correct
IUPAC name is 3-methylhexane. "2-methylhexane" would result from incorrect numbering, while the
other options are based on incorrect parent chain lengths.
2. Which of the following functional groups has the highest priority for IUPAC nomenclature?
A) Alcohol
B) Aldehyde
C) Carboxylic acid
D) Ketone
Correct Answer: Carboxylic acid
Rationale: In IUPAC nomenclature, functional groups are assigned a priority order for choosing the
parent chain and suffix. Carboxylic acids have the highest priority among the common functional
groups, followed by esters, amides, nitriles, aldehydes, ketones, alcohols, and amines. Therefore, a
carboxylic acid will always be the principal functional group.
,3. A molecule is classified as being both aliphatic and heterocyclic. Which of the following structures
fits this description?
A) Benzene
B) Cyclohexane
C) Tetrahydrofuran
D) Pyridine
Correct Answer: Tetrahydrofuran
Rationale: Aliphatic compounds are non-aromatic, and heterocyclic compounds contain a ring with at
least one atom other than carbon. Tetrahydrofuran is a saturated, non-aromatic ring containing an
oxygen atom, fitting both descriptions. Benzene and pyridine are aromatic, and cyclohexane is
carbocyclic (contains only carbon).
4. What is the relationship between the two compounds shown below?
CH₃-CH₂-CH₂-CH₃ and CH₃-CH(CH₃)-CH₃
A) They are the same compound.
B) They are constitutional isomers.
C) They are stereoisomers.
D) They are different compounds with different molecular formulas.
Correct Answer: They are constitutional isomers.
Rationale: Both compounds have the molecular formula C₄H₁₀. The first is the straight-chain butane,
and the second is the branched isobutane (2-methylpropane). They differ in the connectivity of their
atoms, which defines them as constitutional (structural) isomers.
5. Which of the following is the correct structure for 2,2-dimethylbutane?
A) CH₃-C(CH₃)₂-CH₂-CH₃
B) CH₃-CH(CH₃)-CH₂-CH₂-CH₃
C) CH₃-C(CH₃)₂-CH₃
, D) CH₃-CH₂-C(CH₃)₂-CH₂-CH₃
Correct Answer: CH₃-C(CH₃)₂-CH₂-CH₃
Rationale: The parent chain is butane (four carbons). Two methyl groups are attached to the second
carbon. This structure is represented as CH₃-C(CH₃)₂-CH₂-CH₃. The other options have incorrect parent
chain lengths or incorrect placement of substituents.
6. Which of the following statements about the combustion of alkanes is true?
A) Complete combustion of an alkane produces carbon monoxide and water.
B) Complete combustion of an alkane produces carbon dioxide and water.
C) Incomplete combustion of an alkane produces only carbon dioxide.
D) Alkanes do not undergo combustion reactions.
Correct Answer: Complete combustion of an alkane produces carbon dioxide and water.
Rationale: Complete combustion of a hydrocarbon, such as an alkane, in the presence of sufficient
oxygen produces carbon dioxide (CO₂) and water (H₂O). Incomplete combustion produces carbon
monoxide (CO) and/or carbon (soot) along with water.
7. What is the IUPAC name for the following compound?
CH₃-CH₂-CH₂-CH₂-CH₂-CH₂-CH₂-CH₃
A) Octane
B) Octene
C) Octyne
D) Cyclooctane
Correct Answer: Octane
