Class 12 Chemistry Chapter 8 Aldehydes Ketones and Carboxylic Acids MCQs Updated 2024 – MyNoteswala

Q.1: Which of the following compounds is an aldehyde?
(a) Acetone
(b) Acetic acid
(c) Formaldehyde
(d) Benzene

Answer: (c) Formaldehyde
Explanation: Formaldehyde (HCHO) is an aldehyde, characterized by the presence of a formyl group (–CHO).

Q.2: Which of the following is the major product of the reaction of acetone with hydrogen cyanide?
(a) 2-Hydroxypropanenitrile
(b) Acetonitrile
(c) 2-Hydroxy-2-methylpropanenitrile
(d) Propane

Answer: (a) 2-Hydroxypropanenitrile
Explanation: Acetone reacts with hydrogen cyanide to form 2-hydroxypropanenitrile via nucleophilic addition.

Q.3: Which of the following reactions is used to convert an aldehyde to a primary alcohol?
(a) Reduction with NaBH₄
(b) Oxidation with KMnO₄
(c) Nitration with HNO₃
(d) Halogenation with Br₂

Answer: (a) Reduction with NaBH₄
Explanation: Reduction of an aldehyde with sodium borohydride (NaBH₄) converts it to a primary alcohol.

Q.4: Which of the following compounds is a ketone?
(a) Benzaldehyde
(b) Acetone
(c) Methanol
(d) Formic acid

Answer: (b) Acetone
Explanation: Acetone (CH₃COCH₃) is a ketone, characterized by the presence of a carbonyl group (C=O) bonded to two alkyl groups.

Q.5: Which of the following is the major product of the reaction of formaldehyde with Grignard reagent?
(a) Primary alcohol
(b) Secondary alcohol
(c) Tertiary alcohol
(d) Ketone

Answer: (a) Primary alcohol
Explanation: Formaldehyde reacts with a Grignard reagent to form a primary alcohol.

Q.6: Which of the following reactions can be used to distinguish between an aldehyde and a ketone?
(a) Tollen’s test
(b) Ninhydrin test
(c) Benedict’s test
(d) Lucas test

Answer: (a) Tollen’s test
Explanation: Tollen’s test gives a positive result with aldehydes, forming a silver mirror, but ketones do not react.

Q.7: Which of the following is the IUPAC name for CH₃CHO?
(a) Acetaldehyde
(b) Ethanol
(c) Ethanal
(d) Ethanoic acid

Answer: (c) Ethanal
Explanation: The IUPAC name for CH₃CHO is Ethanal.

Q.8: Which of the following is the major product when acetone is treated with dilute NaOH?
(a) Mesityl oxide
(b) Diacetone alcohol
(c) Acetophenone
(d) Benzylideneacetone

Answer: (b) Diacetone alcohol
Explanation: Acetone undergoes aldol condensation in the presence of dilute NaOH to form diacetone alcohol.

Q.9: Which of the following is the major product of the oxidation of ethanol?
(a) Ethanal
(b) Ethene
(c) Methane
(d) Methanol

Answer: (a) Ethanal
Explanation: The oxidation of ethanol produces ethanal (acetaldehyde) as the major product.

Q.10: Which of the following compounds will not undergo the Cannizzaro reaction?
(a) Benzaldehyde
(b) Formaldehyde
(c) Acetone
(d) Trimethylacetaldehyde

Answer: (c) Acetone
Explanation: Acetone is a ketone and does not undergo the Cannizzaro reaction, which is specific to aldehydes without α-hydrogen.

Q.11: Which of the following is the major product of the reaction between acetaldehyde and hydroxylamine?
(a) Oxime
(b) Hydrazone
(c) Semicarbazone
(d) 2,4-Dinitrophenylhydrazone

Answer: (a) Oxime
Explanation: Acetaldehyde reacts with hydroxylamine to form an oxime.

Q.12: Which of the following reagents is used to oxidize a primary alcohol to a carboxylic acid?
(a) PCC
(b) KMnO₄
(c) LiAlH₄
(d) NaBH₄

Answer: (b) KMnO₄
Explanation: Potassium permanganate (KMnO₄) is a strong oxidizing agent that oxidizes primary alcohols to carboxylic acids.

Q.13: Which of the following is the IUPAC name for CH₃COOH?
(a) Acetic acid
(b) Formic acid
(c) Propanoic acid
(d) Ethanoic acid

Answer: (d) Ethanoic acid
Explanation: The IUPAC name for CH₃COOH is Ethanoic acid.

Q.14: Which of the following is the major product when benzaldehyde is treated with concentrated NaOH?
(a) Benzyl alcohol
(b) Benzoic acid
(c) Benzal
(d) Benzylamine

Answer: (b) Benzoic acid
Explanation: Benzaldehyde undergoes Cannizzaro reaction in the presence of concentrated NaOH to form benzoic acid and benzyl alcohol.

Q.15: Which of the following is the major product when acetone is treated with iodine in the presence of NaOH?
(a) Iodoform
(b) Acetaldehyde
(c) Methane
(d) Acetone iodide

Answer: (a) Iodoform
Explanation: Acetone reacts with iodine in the presence of NaOH to form iodoform (CHI₃).

Q.16: Which of the following reactions is used to prepare an aldehyde from an acyl chloride?
(a) Rosenmund reduction
(b) Wurtz reaction
(c) Friedel-Crafts acylation
(d) Cannizzaro reaction

Answer: (a) Rosenmund reduction
Explanation: Rosenmund reduction involves the reduction of acyl chlorides to aldehydes using hydrogen gas and a palladium catalyst.

Q.17: Which of the following is the IUPAC name for C₆H₅CHO?
(a) Benzaldehyde
(b) Benzoic acid
(c) Phenylmethanol
(d) Benzyl alcohol

Answer: (a) Benzaldehyde
Explanation: The IUPAC name for C₆H₅CHO is Benzaldehyde.

Q.18: Which of the following compounds will undergo decarboxylation upon heating with soda lime?
(a) Acetic acid
(b) Benzoic acid
(c) Formic acid
(d) Oxalic acid

Answer: (a) Acetic acid
Explanation: Acetic acid undergoes decarboxylation when heated with soda lime, releasing CO₂ and forming methane.

Q.19: Which of the following is the major product of the reaction of benzaldehyde with acetophenone in the presence of NaOH?
(a) Benzoin
(b) Benzalacetone
(c) Benzyl alcohol
(d) Benzoic acid

Answer: (b) Benzalacetone
Explanation: Benzaldehyde reacts with acetophenone in the presence of NaOH to form benzalacetone via aldol condensation.

Q.20: Which of the following is the major product of the oxidation of 2-propanol?
(a) Propanone
(b) Propanoic acid
(c) Propanal
(d) Propanol

Answer: (a) Propanone
Explanation: The oxidation of 2-propanol produces propanone (acetone) as the major product.

Q.21: Which of the following is the IUPAC name for HCOOH?
(a) Formic acid
(b) Acetic acid
(c) Propanoic acid
(d) Butanoic acid

Answer: (a) Formic acid
Explanation: The IUPAC name for HCOOH is Formic acid.

Q.22: Which of the following reactions is used to convert an aldehyde to a carboxylic acid?
(a) Oxidation with KMnO₄
(b) Reduction with NaBH₄
(c) Nitration with HNO₃
(d) Halogenation with Br₂

Answer: (a) Oxidation with KMnO₄
Explanation: Oxidation of an aldehyde with potassium permanganate (KMnO₄) converts it to a carboxylic acid.

Q.23: Which of the following is the major product when benzene is treated with acyl chloride in the presence of AlCl₃?
(a) Benzaldehyde
(b) Acetophenone
(c) Benzophenone
(d) Benzoic acid

Answer: (b) Acetophenone
Explanation: Benzene reacts with acyl chloride in the presence of AlCl₃ to form acetophenone via Friedel-Crafts acylation.

Q.24: Which of the following compounds will not give a positive Tollen’s test?
(a) Formaldehyde
(b) Acetone
(c) Benzaldehyde
(d) Propanal

Answer: (b) Acetone
Explanation: Acetone is a ketone and does not give a positive Tollen’s test, which is specific for aldehydes.

Q.25: Which of the following is the major product of the reaction between propanoic acid and thionyl chloride?
(a) Propanoyl chloride
(b) Propanol
(c) Propanone
(d) Propanal

Answer: (a) Propanoyl chloride
Explanation: Propanoic acid reacts with thionyl chloride (SOCl₂) to form propanoyl chloride.

Q.26: Which of the following reactions is used to convert a carboxylic acid to an ester?
(a) Esterification with alcohol and acid catalyst
(b) Reduction with NaBH₄
(c) Oxidation with KMnO₄
(d) Hydrolysis with H₂O

Answer: (a) Esterification with alcohol and acid catalyst
Explanation: Esterification of a carboxylic acid with an alcohol in the presence of an acid catalyst produces an ester.

Q.27: Which of the following is the IUPAC name for CH₃COCH₃?
(a) Propanone
(b) Propanal
(c) Propanol
(d) Propanoic acid

Answer: (a) Propanone
Explanation: The IUPAC name for CH₃COCH₃ is Propanone.

Q.28: Which of the following compounds will not undergo nucleophilic addition reactions?
(a) Benzaldehyde
(b) Acetone
(c) Methanal
(d) Ethanoic acid

Answer: (d) Ethanoic acid
Explanation: Ethanoic acid, being a carboxylic acid, does not undergo nucleophilic addition reactions but rather nucleophilic substitution.

Q.29: Which of the following is the major product of the reaction of acetone with methylmagnesium bromide followed by hydrolysis?
(a) 2-Methyl-2-propanol
(b) 2-Propanol
(c) 2-Butanol
(d) 2-Methyl-1-propanol

Answer: (a) 2-Methyl-2-propanol
Explanation: Acetone reacts with methylmagnesium bromide to form 2-methyl-2-propanol upon hydrolysis.

Q.30: Which of the following is the major product of the reaction of benzaldehyde with nitric acid?
(a) Benzoic acid
(b) Benzyl alcohol
(c) Benzophenone
(d) Benzamide

Answer: (a) Benzoic acid
Explanation: Benzaldehyde is oxidized to benzoic acid by nitric acid.

Q.31: Which of the following is the major product of the oxidation of propanal?
(a) Propanoic acid
(b) Propanone
(c) Propanol
(d) Propane

Answer: (a) Propanoic acid
Explanation: Propanal is oxidized to propanoic acid.

Q.32: Which of the following compounds will undergo haloform reaction?
(a) Acetone
(b) Benzaldehyde
(c) Formic acid
(d) Propanone

Answer: (a) Acetone
Explanation: Acetone undergoes haloform reaction to produce iodoform (CHI₃) when treated with iodine and a base.

Q.33: Which of the following is the major product of the reaction of ethanal with dilute NaOH?
(a) Ethanol
(b) Acetaldehyde
(c) Ethene
(d) Ethyl acetate

Answer: (b) Acetaldehyde
Explanation: Ethanal reacts with dilute NaOH to form acetaldehyde via aldol condensation.

Q.34: Which of the following is the major product of the reaction of acetone with phenylhydrazine?
(a) Phenylhydrazone
(b) Oxime
(c) Semicarbazone
(d) 2,4-Dinitrophenylhydrazone

Answer: (a) Phenylhydrazone
Explanation: Acetone reacts with phenylhydrazine to form phenylhydrazone.

Q.35: Which of the following is the major product when methanal is treated with ammonia?
(a) Hexamethylenetetramine
(b) Methanol
(c) Methanamine
(d) Methanamide

Answer: (a) Hexamethylenetetramine
Explanation: Methanal reacts with ammonia to form hexamethylenetetramine.

Q.36: Which of the following is the major product of the reaction of benzaldehyde with hydrogen peroxide?
(a) Benzoic acid
(b) Benzyl alcohol
(c) Benzophenone
(d) Benzamide

Answer: (a) Benzoic acid
Explanation: Benzaldehyde is oxidized to benzoic acid by hydrogen peroxide.

Q.37: Which of the following is the IUPAC name for HCOOCH₃?
(a) Methyl formate
(b) Methyl acetate
(c) Formic acid
(d) Methanol

Answer: (a) Methyl formate
Explanation: The IUPAC name for HCOOCH₃ is Methyl formate.

Q.38: Which of the following is the major product of the reaction of propanone with phenylhydrazine?
(a) Phenylhydrazone
(b) Oxime
(c) Semicarbazone
(d) 2,4-Dinitrophenylhydrazone

Answer: (a) Phenylhydrazone
Explanation: Propanone reacts with phenylhydrazine to form phenylhydrazone.

Q.39: Which of the following is the major product of the reaction of benzaldehyde with semicarbazide?
(a) Semicarbazone
(b) Oxime
(c) Phenylhydrazone
(d) 2,4-Dinitrophenylhydrazone

Answer: (a) Semicarbazone
Explanation: Benzaldehyde reacts with semicarbazide to form semicarbazone.

Q.40: Which of the following is the major product of the reaction of formaldehyde with potassium cyanide?
(a) Formaldehyde cyanohydrin
(b) Formamide
(c) Formic acid
(d) Methanol

Answer: (a) Formaldehyde cyanohydrin
Explanation: Formaldehyde reacts with potassium cyanide to form formaldehyde cyanohydrin.

Q.41: Which of the following compounds will undergo Kolbe’s electrolysis?
(a) Formic acid
(b) Acetic acid
(c) Benzoic acid
(d) Oxalic acid

Answer: (b) Acetic acid
Explanation: Acetic acid undergoes Kolbe’s electrolysis to form ethane.

Q.42: Which of the following is the major product of the reaction of propanone with ammonia?
(a) Propanamide
(b) Propylamine
(c) 2-Aminopropanone
(d) Propanamine

Answer: (c) 2-Aminopropanone
Explanation: Propanone reacts with ammonia to form 2-aminopropanone.

Q.43: Which of the following compounds will undergo esterification with methanol?
(a) Acetic acid
(b) Benzaldehyde
(c) Formic acid
(d) Propanone

Answer: (a) Acetic acid
Explanation: Acetic acid undergoes esterification with methanol to form methyl acetate.

Q.44: Which of the following is the major product of the reaction of benzaldehyde with bromine?
(a) Benzaldehyde dibromide
(b) Benzyl bromide
(c) Benzylidene bromide
(d) Benzal bromide

Answer: (a) Benzaldehyde dibromide
Explanation: Benzaldehyde reacts with bromine to form benzaldehyde dibromide.

Q.45: Which of the following is the major product of the reaction of formaldehyde with hydrogen cyanide?
(a) Formaldehyde cyanohydrin
(b) Formic acid
(c) Methanol
(d) Methanamine

Answer: (a) Formaldehyde cyanohydrin
Explanation: Formaldehyde reacts with hydrogen cyanide to form formaldehyde cyanohydrin.

Q.46: Which of the following is the IUPAC name for HCOCH₃?
(a) Acetaldehyde
(b) Acetone
(c) Formaldehyde
(d) Methanal

Answer: (a) Acetaldehyde
Explanation: The IUPAC name for HCOCH₃ is Acetaldehyde.

Q.47: Which of the following is the major product of the reaction of acetone with phenylhydrazine?
(a) Phenylhydrazone
(b) Oxime
(c) Semicarbazone
(d) 2,4-Dinitrophenylhydrazone

Answer: (a) Phenylhydrazone
Explanation: Acetone reacts with phenylhydrazine to form phenylhydrazone.

Q.48: Which of the following is the major product of the reaction of formaldehyde with ammonia?
(a) Hexamethylenetetramine
(b) Methanol
(c) Methanamine
(d) Methanamide

Answer: (a) Hexamethylenetetramine
Explanation: Formaldehyde reacts with ammonia to form hexamethylenetetramine.

Q.49: Which of the following is the major product of the oxidation of ethanol?
(a) Ethanal
(b) Ethene
(c) Ethanoic acid
(d) Ethanol

Answer: (c) Ethanoic acid
Explanation: Ethanol is oxidized to ethanoic acid.

Q.50: Which of the following is the major product of the reduction of acetone with lithium aluminium hydride?
(a) Propan-1-ol
(b) Propan-2-ol
(c) Ethanol
(d) Methanol

Answer: (b) Propan-2-ol
Explanation: Acetone is reduced to propan-2-ol by lithium aluminium hydride.

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