CHEM 219 Module 1 Exam: Hydrocarbons and IUPAC Naming
2026/2027 update
1. Which of the following is the general formula for a non-cyclic alkane?
A. CnH2n+2
B. CnH2n
C. CnH2n-2
D. CnHn
Answer: A
Rationale: Alkanes are saturated hydrocarbons with the general formula CnH2n+2.
2. What is the hybridization of the carbon atoms in methane (CH4)?
A. sp
B. sp3
C. sp2
D. dsp2
Answer: B
Rationale: In methane, carbon forms four single sigma bonds, which requires sp3
hybridization.
,3. Which suffix is used for a hydrocarbon containing a carbon-carbon double
bond?
A. -ene
B. -yne
C. -ol
D. -ane
Answer: A
Rationale: The suffix -ene denotes an alkene, which contains at least one carbon-carbon
double bond.
4. What is the bond angle in a perfectly tetrahedral molecule like methane?
A. 90 degrees
B. 109.5 degrees
C. 120 degrees
D. 180 degrees
Answer: B
Rationale: The sp3 hybridization results in a tetrahedral geometry with bond angles of
approximately 109.5 degrees.
5. Which of these is the simplest alkyne?
A. Methane
B. Ethene
C. Ethyne
D. Propane
Answer: C
Rationale: Ethyne (acetylene) is the simplest alkyne, consisting of two carbons joined by a
triple bond.
, 6. What is the IUPAC name for a straight-chain alkane with five carbon atoms?
A. Butane
B. Heptane
C. Hexane
D. Pentane
Answer: D
Rationale: The prefix for five carbons is ‘pent-’, followed by the suffix ‘-ane’ for alkanes.
7. How many constitutional isomers does butane (C4H10) have?
A. 1
B. 2
C. 3
D. 4
Answer: B
Rationale: Butane has two isomers: n-butane and isobutane (2-methylpropane).
8. What is the IUPAC name for the group -CH2CH3?
A. Ethyl
B. Methyl
C. Propyl
D. Butyl
Answer: A
Rationale: An ethyl group is a two-carbon alkyl group derived from ethane.
2026/2027 update
1. Which of the following is the general formula for a non-cyclic alkane?
A. CnH2n+2
B. CnH2n
C. CnH2n-2
D. CnHn
Answer: A
Rationale: Alkanes are saturated hydrocarbons with the general formula CnH2n+2.
2. What is the hybridization of the carbon atoms in methane (CH4)?
A. sp
B. sp3
C. sp2
D. dsp2
Answer: B
Rationale: In methane, carbon forms four single sigma bonds, which requires sp3
hybridization.
,3. Which suffix is used for a hydrocarbon containing a carbon-carbon double
bond?
A. -ene
B. -yne
C. -ol
D. -ane
Answer: A
Rationale: The suffix -ene denotes an alkene, which contains at least one carbon-carbon
double bond.
4. What is the bond angle in a perfectly tetrahedral molecule like methane?
A. 90 degrees
B. 109.5 degrees
C. 120 degrees
D. 180 degrees
Answer: B
Rationale: The sp3 hybridization results in a tetrahedral geometry with bond angles of
approximately 109.5 degrees.
5. Which of these is the simplest alkyne?
A. Methane
B. Ethene
C. Ethyne
D. Propane
Answer: C
Rationale: Ethyne (acetylene) is the simplest alkyne, consisting of two carbons joined by a
triple bond.
, 6. What is the IUPAC name for a straight-chain alkane with five carbon atoms?
A. Butane
B. Heptane
C. Hexane
D. Pentane
Answer: D
Rationale: The prefix for five carbons is ‘pent-’, followed by the suffix ‘-ane’ for alkanes.
7. How many constitutional isomers does butane (C4H10) have?
A. 1
B. 2
C. 3
D. 4
Answer: B
Rationale: Butane has two isomers: n-butane and isobutane (2-methylpropane).
8. What is the IUPAC name for the group -CH2CH3?
A. Ethyl
B. Methyl
C. Propyl
D. Butyl
Answer: A
Rationale: An ethyl group is a two-carbon alkyl group derived from ethane.
