Q.1 Which of the following is an aldehyde?
CH3CH2OH
CH3CHO
CH3COCH3
CH3COOH
Explanation - CH3CHO (ethanal) has the -CHO functional group characteristic of aldehydes.
Correct answer is: CH3CHO
Q.2 Which reagent is commonly used to distinguish aldehydes from ketones?
Bromine water
Tollens' reagent
Fehling's solution
Sodium hydroxide
Explanation - Tollens' reagent oxidizes aldehydes to carboxylic acids but does not react with ketones.
Correct answer is: Tollens' reagent
Q.3 Which of the following ketones has the highest boiling point?
CH3COCH3
CH3CH2COCH3
CH3CH2CH2COCH3
CH3COCH2CH3
Explanation - Boiling points increase with molecular weight due to stronger van der Waals forces.
Correct answer is: CH3CH2CH2COCH3
Q.4 Which of the following undergoes Cannizzaro reaction?
Formaldehyde
Acetaldehyde
Acetone
Benzaldehyde
Explanation - Aldehydes without alpha-hydrogen, like benzaldehyde, undergo the Cannizzaro reaction.
Correct answer is: Benzaldehyde
Q.5 The product of oxidation of primary alcohol is:
Ketone
Aldehyde
Carboxylic acid
Ether
Explanation - Primary alcohol oxidizes first to aldehyde and can further oxidize to carboxylic acid.
Correct answer is: Aldehyde
Q.6 Which of the following acids is strongest?
HCOOH
CH3COOH
C6H5COOH
CH3CH2COOH
Explanation - Formic acid (HCOOH) is more acidic due to the absence of electron-donating alkyl groups.
Correct answer is: HCOOH
Q.7 Which of the following undergoes aldol condensation?
Acetaldehyde
Acetone
Formaldehyde
All of the above
Explanation - Aldol condensation occurs for aldehydes and ketones with at least one alpha-hydrogen.
Correct answer is: All of the above
Q.8 Which reagent is used for the oxidation of aldehydes to carboxylic acids?
PCC
KMnO4
LiAlH4
NaBH4
Explanation - Potassium permanganate (KMnO4) is a strong oxidizing agent converting aldehydes to carboxylic acids.
Correct answer is: KMnO4
Q.9 Which of the following is a beta-hydroxyketone?
CH3CH(OH)CH3
CH3CH2CH(OH)COCH3
CH3CHO
CH3COOH
Explanation - A beta-hydroxyketone has a hydroxyl group on the beta-carbon relative to the carbonyl group.
Correct answer is: CH3CH2CH(OH)COCH3
Q.10 Which compound gives a silver mirror with Tollens’ reagent?
Acetone
Ethanal
Propanone
Cyclohexanone
Explanation - Aldehydes like ethanal reduce Tollens’ reagent to metallic silver, forming a silver mirror.
Correct answer is: Ethanal
Q.11 Which of the following is a characteristic reaction of carboxylic acids?
Fischer esterification
Bromination
Cannizzaro reaction
Aldol condensation
Explanation - Carboxylic acids react with alcohols in the presence of acid to form esters (Fischer esterification).
Correct answer is: Fischer esterification
Q.12 The IUPAC name of CH3CH2COOH is:
Propanoic acid
Butanoic acid
Ethanoic acid
Methanoic acid
Explanation - CH3CH2COOH has three carbon atoms; thus the IUPAC name is propanoic acid.
Correct answer is: Propanoic acid
Q.13 Which of the following is a reaction of aldehydes with ammonia derivatives?
Cannizzaro reaction
Schiff's base formation
Aldol condensation
Esterification
Explanation - Aldehydes react with primary amines to form imines, also called Schiff’s bases.
Correct answer is: Schiff's base formation
Q.14 Which of the following cannot be oxidized further by mild oxidizing agents?
CH3CHO
CH3COCH3
HCOOH
C6H5CHO
Explanation - Ketones like CH3COCH3 do not have a hydrogen on the carbonyl carbon and resist oxidation by mild oxidizing agents.
Correct answer is: CH3COCH3
Q.15 Which of the following acids is aromatic?
Formic acid
Acetic acid
Benzoic acid
Propanoic acid
Explanation - Benzoic acid has a benzene ring, making it aromatic.
Correct answer is: Benzoic acid
Q.16 Which of the following compounds reacts with 2,4-DNP to give an orange precipitate?
CH3CH2OH
CH3CHO
CH3COOH
CH4
Explanation - Aldehydes and ketones react with 2,4-dinitrophenylhydrazine (2,4-DNP) to give a yellow/orange precipitate.
Correct answer is: CH3CHO
Q.17 Which reagent selectively oxidizes primary alcohols to aldehydes without further oxidation?
PCC
KMnO4
K2Cr2O7
H2O2
Explanation - Pyridinium chlorochromate (PCC) oxidizes primary alcohols to aldehydes without producing carboxylic acids.
Correct answer is: PCC
Q.18 Which carboxylic acid derivative is most reactive towards nucleophilic substitution?
Acid chloride
Amide
Ester
Carboxylic acid
Explanation - Acid chlorides are highly reactive due to the good leaving ability of Cl-.
Correct answer is: Acid chloride
Q.19 Which of the following is the product of aldol condensation of acetaldehyde?
CH3CH2CHO
CH3CH=CHCHO
CH3CH(OH)CH2CHO
CH3COCH3
Explanation - Initial aldol condensation produces a beta-hydroxyaldehyde.
Correct answer is: CH3CH(OH)CH2CHO
Q.20 Which of the following compounds is more acidic?
CH3COOH
CH3CH2COOH
C6H5COOH
HCOOH
Explanation - Formic acid (HCOOH) is more acidic than other carboxylic acids due to the absence of electron-donating alkyl groups.
Correct answer is: HCOOH
Q.21 Which of the following undergoes haloform reaction?
CH3CHO
CH3COCH3
CH3CH2OH
CH3CH2COOH
Explanation - Methyl ketones (like CH3COCH3) react with halogens in the presence of base to give haloform.
Correct answer is: CH3COCH3
Q.22 Which of the following is the IUPAC name of CH3COCH3?
Propanone
Propanal
Acetone
Propanoic acid
Explanation - CH3COCH3 is a ketone with three carbon atoms; IUPAC name is propanone.
Correct answer is: Propanone
Q.23 Which reagent converts carboxylic acids into alcohols?
LiAlH4
KMnO4
PCC
Tollens’ reagent
Explanation - Lithium aluminium hydride (LiAlH4) is a strong reducing agent that reduces carboxylic acids to primary alcohols.
Correct answer is: LiAlH4
Q.24 Which of the following reactions is used to test the presence of aldehydes?
Benedict’s test
Tollens’ test
Bromination
Saponification
Explanation - Tollens’ test distinguishes aldehydes from ketones, forming a silver mirror in presence of aldehydes.
Correct answer is: Tollens’ test