Free Aldehydes and Ketones MCQs with Answers
679 Aldehydes and Ketones MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Aldehydes and ketones contain the polar carbonyl group, but aldehydes are generally more readily oxidised and more reactive than ketones. Coverage includes preparation by oxidation or reduction routes, nucleophilic addition of reagents such as hydrogen cyanide and bisulfite, and tests that distinguish aldehydes from ketones.
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679 questions · page 18 of 34
- A. Trigonal
- B. Linear
- C. Tetrahedral
- D. Square planer
Explanation: Option C is correct as acetal is the product of condensation of two alcohol molecules with an aldehyde to form a "tetrahedral structure".
Correct answer: Tetrahedral- A. Acetal
- B. Ketal
- C. Carboxylic acid
- D. Alcohol
Explanation: Option A is correct since when alcohol is added to aldehyde, an acetal is formed.Option B is incorrect since ketal is formed when ketone…
Correct answer: Acetal- A. Acetic acid and acid amide
- B. Acetic acid and ammonia
- C. Acetic acid and methyl chloride
- D. Acetic acid and ammonium chloride
Explanation: Chemical reaction: 2CH3CN + 2HCl + 4H2O → 2CH3COOH (acetic acid) +2NH4Cl (ammonium chloride).
Correct answer: Acetic acid and ammonium chloride- A. Nucleophilic
- B. Electrophilic
- C. Neutral
- D. All of these
Explanation: Carbon attached to the aldehyde group is electron deficient due to highly electronegative oxygen being bonded to it, thus acting as an…
Correct answer: Electrophilic- A. Nucleophilic substitution
- B. Electrophilic addition
- C. Nucleophilic addition
- D. Electrophilic substitution
Explanation: The formation of cyanohydrin is achieved by addition of HCN to carbonyl compounds.
Correct answer: Nucleophilic addition- A. Formaldehyde
- B. Acetaldehyde
- C. Benzaldehyde
- D. Acetone
Explanation: Acetone is a ketone, and it shows a rapid reaction with sodium nitroprusside due to the presence of the methyl group adjacent to the…
Correct answer: Acetone- A. α-C
- B. α-H
- C. Basic medium
- D. All of these
Explanation: All of the conditions mentioned (α-C, α-H, and a basic medium) are necessary for aldol condensation to occur, making option D, "All of…
Correct answer: All of these- A. Grignard reagent
- B. 2,4-DNPH
- C. Polymerization
- D. HCN
Explanation: Ketones generally do not undergo polymerization reactions under typical conditions.
Correct answer: Polymerization- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Cleavage of ether linkages, acyl-oxygen cleavage by acidic hydrolysis and further decarboxylation leads to cyclohexanone.
Correct answer: Option C- A. (I) > (II) > (III)
- B. (III) > (I) > (II)
- C. (II) > (I) > (III)
- D. (II) > (III) > (I)
Explanation: Reactivity of carbonyl compounds with any nucleophile is based on the electrophilicity of the carbonyl carbon and steric crowding around…
Correct answer: (II) > (III) > (I)- A. I < II < III < IV
- B. IV < III < II < I
- C. III < II < IV < I
- D. III < IV < II < I
Explanation: Hydrate formation involves nucleophilic addition at carbonyl carbon in the slow rate determining step.
Correct answer: III < IV < II < I- A. CH3CHO
- B. CH3COCH3
- C. CH3COCH2CHO
- D. CH3COCH2COOCH3
Explanation: Hydrogen atoms present at alpha-position to any electron withdrawing substituent are acidic in nature.
Correct answer: CH3COCH2CHO- A. benzyl alcohol and sodium formate.
- B. sodium benzoate and methyl alcohol.
- C. sodium benzoate and sodium formate.
- D. benzyl alcohol and sodium benzoate.
Explanation: This is a crossed Cannizzaro reaction. Formaldehyde has no α-hydrogen and its carbonyl carbon is more electrophilic and less sterically…
Correct answer: benzyl alcohol and sodium formate.- A. Phenol
- B. Carboxylic acid
- C. Ethyl alcohol
- D. Ether
Explanation: Carboxylic acid is the most acidic among all. The increasing order of acidity of compounds are: Ether < Ethyl alcohol < Phenol <…
Correct answer: Carboxylic acid- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Greater the charge density on carbon of the C−H group, the greater the tendency of the hydride to leave the carbon atom.
Correct answer: Option C- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Ether neither reacts with Na metal nor gives a postive 2,4 -DNPH test.
Correct answer: Option D- A. sp2-hybridized oxygen atom
- B. Only one hydrogen atom
- C. Only one carbon atom
- D. At least two carbon atom
Explanation: Carbonyl compounds include aldehyde and kerones. Aldehydes have structural formula.
Correct answer: At least two carbon atom- A. Formaldehyde
- B. Crotanaldehyde
- C. Acetaldehyde
- D. Butyraldehyde
Explanation: Mostly in saturated and aliphatic carbonyl compounds the carbonyl carbon is bonded to one or two sp3 hybridized carbon atoms but…
Correct answer: Formaldehyde- A. (CH3)2CO
- B. C3H7COCH2CH2CH3
- C. C2H3OC2H5
- D. C2H5CO(CH2)2CH3
Explanation: The unsymmetrical ketones have two different alkyl groups on either side of carbonyl group like
Correct answer: C2H5CO(CH2)2CH3- A. Pt-asbestos
- B. FeO and Mo2O3
- C. Na2Cr2O7 and H2SO4
- D. All of these
Explanation: FeO, MO2O3 and Pt-asbestos are catalysts used for air oxidation of alcohols to aldehydes while Na2Cr2O7+H2SO4 combination is used for the…
Correct answer: All of these