Aldehydes, and Ketones 2026/2027 UPDATE
1. What is the general formula for a saturated acyclic alcohol?
A. CnH2nO
B. CnH2n+2O2
C. CnH2n+1OH
D. CnHnOH
Answer: C
Rationale: A saturated acyclic alcohol follows the general formula CnH2n+1OH or
CnH2n+2O, where the hydroxyl group replaces one hydrogen in an alkane.
2. Which of the following describes a secondary (2°) alcohol?
A. The OH group is attached to a carbon bonded to two other carbons.
B. The OH group is attached to a carbon bonded to three other carbons.
C. The OH group is attached to a carbon bonded to one other carbon.
D. The OH group is attached to a terminal carbon.
Answer: A
Rationale: In a secondary alcohol, the carbon atom bearing the hydroxyl group is directly
attached to two other carbon atoms.
,3. What is the IUPAC name for the compound CH3CH2CH(OH)CH3?
A. 1-butanol
B. Butan-3-ol
C. Isopropanol
D. 2-butanol
Answer: D
Rationale: The longest chain has 4 carbons (butane), and the OH group is on the second
carbon, making it 2-butanol.
4. Which alcohol is commonly known as wood alcohol?
A. Methanol
B. Isopropyl alcohol
C. Ethanol
D. Ethylene glycol
Answer: A
Rationale: Methanol was historically produced by the destructive distillation of wood,
earning it the name wood alcohol.
5. Which of the following compounds has the highest boiling point?
A. Ethane
B. Dimethyl ether
C. Chloromethane
D. Ethanol
Answer: D
Rationale: Ethanol can form intermolecular hydrogen bonds due to its hydroxyl group,
leading to a significantly higher boiling point than ethers or alkanes of similar mass.
, 6. What is the result of the mild oxidation of a primary alcohol?
A. Ketone
B. Ether
C. Alkene
D. Aldehyde
Answer: D
Rationale: Primary alcohols are oxidized first to aldehydes. Further oxidation leads to
carboxylic acids.
7. Which reagent is typically used to distinguish between primary, secondary,
and tertiary alcohols?
A. Tollens’ reagent
B. Lucas reagent
C. Benedict’s solution
D. Fehling’s solution
Answer: B
Rationale: Lucas reagent (ZnCl2 in conc. HCl) reacts at different rates: tertiary alcohols
react immediately (cloudy), secondary alcohols take 5-10 minutes, and primary alcohols
generally do not react at room temperature.
8. Tertiary alcohols are resistant to oxidation because:
A. They are too bulky.
B. There is no hydrogen atom on the carbon bearing the OH group.
C. The OH group is too reactive.
D. They form stable ethers instead.
Answer: B
Rationale: Oxidation of an alcohol requires the removal of a hydrogen from the hydroxyl
group and a hydrogen from the alpha-carbon. Tertiary alcohols lack this alpha-hydrogen.