CHEM 219 Principles Of Organic Chemistry-
Final Exam | All Questions And Solutions
(Rationales) | Exam Prep Q&A 2026/2027
1. A student reacts 1-bromobutane with sodium hydroxide in aqueous solution under
conditions favoring nucleophilic substitution. Which product is expected to form as the
major organic product?
A. But-1-ene
B. Butan-2-ol
C. Butan-1-ol
D. Butanal
Rationale: Hydroxide ions act as nucleophiles and replace bromide in primary 1-bromobutane
through an SN2 mechanism. The major substitution product is butan-1-ol.
2. During a laboratory practical, a technician must distinguish between cyclohexane and
cyclohexene. Which test provides the clearest initial distinction under suitable conditions?
A. Add bromine solution and observe whether its color disappears without requiring
ultraviolet light.
B. Add sodium chloride solution and look for a white precipitate.
C. Add dilute sodium hydroxide and measure the pH change.
D. Add distilled water and determine which liquid produces hydrogen gas.
Rationale: Cyclohexene contains a carbon-carbon double bond that reacts with bromine by
electrophilic addition, rapidly decolorizing the bromine solution under suitable conditions.
Cyclohexane generally does not react under these conditions without an appropriate
initiation process such as ultraviolet irradiation.
3. Which statement correctly explains why carbon forms a particularly large variety of
organic compounds?
A. Carbon forms only ionic bonds with other elements.
B. Carbon cannot form multiple bonds.
,C. Carbon has six valence electrons available for bonding.
D. Carbon forms stable covalent bonds with itself and many other elements, allowing chains,
rings, and multiple bonds.
Rationale: Carbon is tetravalent and forms stable covalent bonds with itself and many other
elements. Catenation, branching, ring formation, and multiple bonding produce the structural
diversity of organic compounds.
4. A compound has the molecular formula C₄H₁₀O and reacts with sodium metal to release
hydrogen gas. Which functional group is most consistent with this observation?
A. Ether
B. Alcohol
C. Aldehyde
D. Ketone
Rationale: Alcohols contain an O–H bond and can react with sodium metal to produce an
alkoxide and hydrogen gas. Ethers lack an O–H bond and do not undergo this characteristic
reaction under ordinary test conditions.
5. A chemist prepares an organic compound containing a carbonyl group bonded to a
hydrogen atom. Which functional group does the compound contain?
A. Ketone
B. Carboxylic acid
C. Aldehyde
D. Ester
Rationale: An aldehyde contains a terminal carbonyl group in which the carbonyl carbon is
bonded to at least one hydrogen atom. A ketone instead has the carbonyl carbon bonded to
two carbon-containing groups.
6. A student draws the structure CH₃CH₂CH(CH₃)CH₃ and must identify its correct
IUPAC name. Which name should be selected?
A. 2-Methylbutane
B. 3-Methylbutane
,C. Pentane
D. 2-Ethylpropane
Rationale: The longest continuous carbon chain contains four carbon atoms, so the parent is
butane. Numbering from the nearer end gives the methyl substituent the lowest possible
locant, 2, producing 2-methylbutane.
7. Which type of isomerism occurs when compounds have the same molecular formula but
differ in the connectivity of their atoms?
A. Optical isomerism
B. Geometrical isomerism
C. Conformational isomerism
D. Structural isomerism
Rationale: Structural isomers have the same molecular formula but different atom-to-atom
connectivity. They may differ in their carbon skeleton, functional group, or the position of a
functional group.
8. A laboratory group compares ethane and ethene. Which statement correctly describes
their carbon-carbon bonds?
A. Ethane contains a carbon-carbon triple bond.
B. Ethane contains a single bond, whereas ethene contains a double bond.
C. Both compounds contain carbon-carbon double bonds.
D. Ethene contains only carbon-carbon single bonds.
Rationale: Ethane, C₂H₆, contains a carbon-carbon single bond, while ethene, C₂H₄, contains a
carbon-carbon double bond. The additional bond in ethene affects its geometry and
characteristic addition reactions.
9. A student needs to prepare an alkene from an alcohol in an organic chemistry
experiment. Which reaction is most appropriate?
A. Oxidation of the alcohol using a mild oxidizing agent
B. Reduction of the alcohol with sodium borohydride
, C. Dehydration of the alcohol under suitable acidic and thermal conditions
D. Neutralization of the alcohol with sodium chloride
Rationale: Dehydration removes water from an alcohol and can produce an alkene. The
conditions and alcohol structure influence the reaction mechanism and the major alkene
formed.
10. Which reagent is commonly used to distinguish a terminal alkyne from an alkene
through formation of a metal acetylide under appropriate conditions?
A. Aqueous sodium chloride
B. Dilute hydrochloric acid alone
C. Bromine-free distilled water
D. Ammoniacal silver nitrate
Rationale: A terminal alkyne has an acidic hydrogen attached to an sp-hybridized carbon and
can form a silver acetylide precipitate with suitable ammoniacal silver(I) reagents. Most
ordinary alkenes do not give this characteristic reaction. Silver acetylides can be hazardous if
allowed to dry, so such tests require appropriate laboratory precautions.
11. A student adds hydrogen gas to ethene in the presence of a suitable metal catalyst.
Which product is expected?
A. Ethane
B. Ethanol
C. Ethanal
D. Ethanoic acid
Rationale: Catalytic hydrogenation adds hydrogen across the carbon-carbon double bond of
ethene, converting it into the saturated alkane ethane. Nickel, palladium, or platinum may be
used as catalysts under suitable conditions.
12. During a reaction, an alkene is treated with hydrogen bromide in the absence of
peroxides. For an unsymmetrical alkene under ordinary ionic conditions, which principle
generally predicts the major product?
A. Anti-Markovnikov addition applies to every hydrogen halide reaction.
Final Exam | All Questions And Solutions
(Rationales) | Exam Prep Q&A 2026/2027
1. A student reacts 1-bromobutane with sodium hydroxide in aqueous solution under
conditions favoring nucleophilic substitution. Which product is expected to form as the
major organic product?
A. But-1-ene
B. Butan-2-ol
C. Butan-1-ol
D. Butanal
Rationale: Hydroxide ions act as nucleophiles and replace bromide in primary 1-bromobutane
through an SN2 mechanism. The major substitution product is butan-1-ol.
2. During a laboratory practical, a technician must distinguish between cyclohexane and
cyclohexene. Which test provides the clearest initial distinction under suitable conditions?
A. Add bromine solution and observe whether its color disappears without requiring
ultraviolet light.
B. Add sodium chloride solution and look for a white precipitate.
C. Add dilute sodium hydroxide and measure the pH change.
D. Add distilled water and determine which liquid produces hydrogen gas.
Rationale: Cyclohexene contains a carbon-carbon double bond that reacts with bromine by
electrophilic addition, rapidly decolorizing the bromine solution under suitable conditions.
Cyclohexane generally does not react under these conditions without an appropriate
initiation process such as ultraviolet irradiation.
3. Which statement correctly explains why carbon forms a particularly large variety of
organic compounds?
A. Carbon forms only ionic bonds with other elements.
B. Carbon cannot form multiple bonds.
,C. Carbon has six valence electrons available for bonding.
D. Carbon forms stable covalent bonds with itself and many other elements, allowing chains,
rings, and multiple bonds.
Rationale: Carbon is tetravalent and forms stable covalent bonds with itself and many other
elements. Catenation, branching, ring formation, and multiple bonding produce the structural
diversity of organic compounds.
4. A compound has the molecular formula C₄H₁₀O and reacts with sodium metal to release
hydrogen gas. Which functional group is most consistent with this observation?
A. Ether
B. Alcohol
C. Aldehyde
D. Ketone
Rationale: Alcohols contain an O–H bond and can react with sodium metal to produce an
alkoxide and hydrogen gas. Ethers lack an O–H bond and do not undergo this characteristic
reaction under ordinary test conditions.
5. A chemist prepares an organic compound containing a carbonyl group bonded to a
hydrogen atom. Which functional group does the compound contain?
A. Ketone
B. Carboxylic acid
C. Aldehyde
D. Ester
Rationale: An aldehyde contains a terminal carbonyl group in which the carbonyl carbon is
bonded to at least one hydrogen atom. A ketone instead has the carbonyl carbon bonded to
two carbon-containing groups.
6. A student draws the structure CH₃CH₂CH(CH₃)CH₃ and must identify its correct
IUPAC name. Which name should be selected?
A. 2-Methylbutane
B. 3-Methylbutane
,C. Pentane
D. 2-Ethylpropane
Rationale: The longest continuous carbon chain contains four carbon atoms, so the parent is
butane. Numbering from the nearer end gives the methyl substituent the lowest possible
locant, 2, producing 2-methylbutane.
7. Which type of isomerism occurs when compounds have the same molecular formula but
differ in the connectivity of their atoms?
A. Optical isomerism
B. Geometrical isomerism
C. Conformational isomerism
D. Structural isomerism
Rationale: Structural isomers have the same molecular formula but different atom-to-atom
connectivity. They may differ in their carbon skeleton, functional group, or the position of a
functional group.
8. A laboratory group compares ethane and ethene. Which statement correctly describes
their carbon-carbon bonds?
A. Ethane contains a carbon-carbon triple bond.
B. Ethane contains a single bond, whereas ethene contains a double bond.
C. Both compounds contain carbon-carbon double bonds.
D. Ethene contains only carbon-carbon single bonds.
Rationale: Ethane, C₂H₆, contains a carbon-carbon single bond, while ethene, C₂H₄, contains a
carbon-carbon double bond. The additional bond in ethene affects its geometry and
characteristic addition reactions.
9. A student needs to prepare an alkene from an alcohol in an organic chemistry
experiment. Which reaction is most appropriate?
A. Oxidation of the alcohol using a mild oxidizing agent
B. Reduction of the alcohol with sodium borohydride
, C. Dehydration of the alcohol under suitable acidic and thermal conditions
D. Neutralization of the alcohol with sodium chloride
Rationale: Dehydration removes water from an alcohol and can produce an alkene. The
conditions and alcohol structure influence the reaction mechanism and the major alkene
formed.
10. Which reagent is commonly used to distinguish a terminal alkyne from an alkene
through formation of a metal acetylide under appropriate conditions?
A. Aqueous sodium chloride
B. Dilute hydrochloric acid alone
C. Bromine-free distilled water
D. Ammoniacal silver nitrate
Rationale: A terminal alkyne has an acidic hydrogen attached to an sp-hybridized carbon and
can form a silver acetylide precipitate with suitable ammoniacal silver(I) reagents. Most
ordinary alkenes do not give this characteristic reaction. Silver acetylides can be hazardous if
allowed to dry, so such tests require appropriate laboratory precautions.
11. A student adds hydrogen gas to ethene in the presence of a suitable metal catalyst.
Which product is expected?
A. Ethane
B. Ethanol
C. Ethanal
D. Ethanoic acid
Rationale: Catalytic hydrogenation adds hydrogen across the carbon-carbon double bond of
ethene, converting it into the saturated alkane ethane. Nickel, palladium, or platinum may be
used as catalysts under suitable conditions.
12. During a reaction, an alkene is treated with hydrogen bromide in the absence of
peroxides. For an unsymmetrical alkene under ordinary ionic conditions, which principle
generally predicts the major product?
A. Anti-Markovnikov addition applies to every hydrogen halide reaction.
