,Verified CHEM 219 Module 5 Exam Principles of
Organic Chemistry w/Lab | Portage (2026–2027)
Actual(PDF)
1. What is the correct IUPAC name for the compound CH₃-CH(OH)-CH₂-CH₂-CH₃?
A) 2-pentanol
B) 3-pentanol
C) 2-pentanone
D) Pentan-2-ol
Correct Answer: 2-pentanol
Rationale: The longest carbon chain contains five carbons, making the parent alkane pentane. The
hydroxyl (-OH) group is the principal functional group, taking the suffix "-ol". Numbering the chain
from the end closest to the -OH gives the hydroxyl group at carbon 2. Therefore, the correct IUPAC
name is 2-pentanol. 3-pentanol would have the -OH at carbon 3.
2. Which of the following correctly ranks the following alcohols in order of increasing boiling point: 1-
butanol, 2-butanol, 2-methyl-2-propanol?
A) 1-butanol < 2-butanol < 2-methyl-2-propanol
B) 2-methyl-2-propanol < 2-butanol < 1-butanol
C) 2-butanol < 1-butanol < 2-methyl-2-propanol
D) 2-methyl-2-propanol < 1-butanol < 2-butanol
Correct Answer: 2-methyl-2-propanol < 2-butanol < 1-butanol
Rationale: Boiling point in alcohols is influenced by molecular weight and the ability to form hydrogen
bonds. For isomeric alcohols, the boiling point decreases with increased branching because branching
reduces the surface area and the effectiveness of intermolecular hydrogen bonding. The straight-chain
primary alcohol (1-butanol) has the highest boiling point, followed by the secondary (2-butanol), and
the tertiary (2-methyl-2-propanol) has the lowest.
,3. Which of the following is the major product of the acid-catalyzed dehydration of 2-methyl-2-
butanol?
A) 2-methyl-1-butene
B) 2-methyl-2-butene
C) 3-methyl-1-butene
D) 2,3-dimethyl-2-butene
Correct Answer: 2-methyl-2-butene
Rationale: Acid-catalyzed dehydration of an alcohol follows Zaitsev's rule, where the more substituted
alkene is the major product. Dehydration of 2-methyl-2-butanol ((CH₃)₂C(OH)-CH₂-CH₃) gives 2-methyl-
2-butene ((CH₃)₂C=CH-CH₃) as the major product. This is a trisubstituted alkene, which is more stable
than the disubstituted 2-methyl-1-butene.
4. Which of the following reagents would be used to convert a primary alcohol to an aldehyde without
further oxidation?
A) KMnO₄ (hot, concentrated)
B) K₂Cr₂O₇ (Jones reagent)
C) PCC (pyridinium chlorochromate)
D) H₂SO₄ (concentrated)
Correct Answer: PCC (pyridinium chlorochromate)
Rationale: PCC is a mild oxidizing agent that selectively oxidizes primary alcohols to aldehydes.
Stronger oxidizing agents like KMnO₄ or Jones reagent (K₂Cr₂O₇/H₂SO₄) will further oxidize the
aldehyde to a carboxylic acid. PCC stops at the aldehyde stage and is therefore the reagent of choice
for this transformation.
5. In the Williamson ether synthesis, an alkoxide ion reacts with a primary alkyl halide. Which of the
following is the correct mechanism for this reaction?
A) SN1
, B) SN2
C) E1
D) E2
Correct Answer: SN2
Rationale: The Williamson ether synthesis involves the reaction of an alkoxide ion (a strong
nucleophile) with a primary alkyl halide. The reaction proceeds via an SN2 mechanism because
primary alkyl halides are excellent substrates for SN2, and the alkoxide is a strong nucleophile.
Secondary and tertiary alkyl halides are avoided due to competing elimination.
6. What is the product of the reaction of 1-butanol with HBr?
A) 1-bromobutane
B) 2-bromobutane
C) 1-butene
D) Butane
Correct Answer: 1-bromobutane
Rationale: Primary alcohols react with HBr via an SN2 mechanism to form primary alkyl bromides. 1-
butanol (CH₃-CH₂-CH₂-CH₂OH) reacts with HBr to give 1-bromobutane (CH₃-CH₂-CH₂-CH₂Br). The
reaction involves protonation of the -OH group, followed by nucleophilic attack of the bromide ion.
7. Which of the following is the correct structure for ethylene oxide (an epoxide)?
A) A three-membered ring containing one oxygen atom and two carbon atoms.
B) A four-membered ring containing one oxygen atom and three carbon atoms.
C) A three-membered ring containing two oxygen atoms and one carbon atom.
D) A five-membered ring containing one oxygen atom and four carbon atoms.
Correct Answer: A three-membered ring containing one oxygen atom and two carbon atoms.
Organic Chemistry w/Lab | Portage (2026–2027)
Actual(PDF)
1. What is the correct IUPAC name for the compound CH₃-CH(OH)-CH₂-CH₂-CH₃?
A) 2-pentanol
B) 3-pentanol
C) 2-pentanone
D) Pentan-2-ol
Correct Answer: 2-pentanol
Rationale: The longest carbon chain contains five carbons, making the parent alkane pentane. The
hydroxyl (-OH) group is the principal functional group, taking the suffix "-ol". Numbering the chain
from the end closest to the -OH gives the hydroxyl group at carbon 2. Therefore, the correct IUPAC
name is 2-pentanol. 3-pentanol would have the -OH at carbon 3.
2. Which of the following correctly ranks the following alcohols in order of increasing boiling point: 1-
butanol, 2-butanol, 2-methyl-2-propanol?
A) 1-butanol < 2-butanol < 2-methyl-2-propanol
B) 2-methyl-2-propanol < 2-butanol < 1-butanol
C) 2-butanol < 1-butanol < 2-methyl-2-propanol
D) 2-methyl-2-propanol < 1-butanol < 2-butanol
Correct Answer: 2-methyl-2-propanol < 2-butanol < 1-butanol
Rationale: Boiling point in alcohols is influenced by molecular weight and the ability to form hydrogen
bonds. For isomeric alcohols, the boiling point decreases with increased branching because branching
reduces the surface area and the effectiveness of intermolecular hydrogen bonding. The straight-chain
primary alcohol (1-butanol) has the highest boiling point, followed by the secondary (2-butanol), and
the tertiary (2-methyl-2-propanol) has the lowest.
,3. Which of the following is the major product of the acid-catalyzed dehydration of 2-methyl-2-
butanol?
A) 2-methyl-1-butene
B) 2-methyl-2-butene
C) 3-methyl-1-butene
D) 2,3-dimethyl-2-butene
Correct Answer: 2-methyl-2-butene
Rationale: Acid-catalyzed dehydration of an alcohol follows Zaitsev's rule, where the more substituted
alkene is the major product. Dehydration of 2-methyl-2-butanol ((CH₃)₂C(OH)-CH₂-CH₃) gives 2-methyl-
2-butene ((CH₃)₂C=CH-CH₃) as the major product. This is a trisubstituted alkene, which is more stable
than the disubstituted 2-methyl-1-butene.
4. Which of the following reagents would be used to convert a primary alcohol to an aldehyde without
further oxidation?
A) KMnO₄ (hot, concentrated)
B) K₂Cr₂O₇ (Jones reagent)
C) PCC (pyridinium chlorochromate)
D) H₂SO₄ (concentrated)
Correct Answer: PCC (pyridinium chlorochromate)
Rationale: PCC is a mild oxidizing agent that selectively oxidizes primary alcohols to aldehydes.
Stronger oxidizing agents like KMnO₄ or Jones reagent (K₂Cr₂O₇/H₂SO₄) will further oxidize the
aldehyde to a carboxylic acid. PCC stops at the aldehyde stage and is therefore the reagent of choice
for this transformation.
5. In the Williamson ether synthesis, an alkoxide ion reacts with a primary alkyl halide. Which of the
following is the correct mechanism for this reaction?
A) SN1
, B) SN2
C) E1
D) E2
Correct Answer: SN2
Rationale: The Williamson ether synthesis involves the reaction of an alkoxide ion (a strong
nucleophile) with a primary alkyl halide. The reaction proceeds via an SN2 mechanism because
primary alkyl halides are excellent substrates for SN2, and the alkoxide is a strong nucleophile.
Secondary and tertiary alkyl halides are avoided due to competing elimination.
6. What is the product of the reaction of 1-butanol with HBr?
A) 1-bromobutane
B) 2-bromobutane
C) 1-butene
D) Butane
Correct Answer: 1-bromobutane
Rationale: Primary alcohols react with HBr via an SN2 mechanism to form primary alkyl bromides. 1-
butanol (CH₃-CH₂-CH₂-CH₂OH) reacts with HBr to give 1-bromobutane (CH₃-CH₂-CH₂-CH₂Br). The
reaction involves protonation of the -OH group, followed by nucleophilic attack of the bromide ion.
7. Which of the following is the correct structure for ethylene oxide (an epoxide)?
A) A three-membered ring containing one oxygen atom and two carbon atoms.
B) A four-membered ring containing one oxygen atom and three carbon atoms.
C) A three-membered ring containing two oxygen atoms and one carbon atom.
D) A five-membered ring containing one oxygen atom and four carbon atoms.
Correct Answer: A three-membered ring containing one oxygen atom and two carbon atoms.
