Aldehydes and Ketones MCQs for NEET

 

Aldehydes and Ketones - NEET MCQs

1. Which of the following is the correct IUPAC name of CH₃CHO?
   a) Methanal
   b) Ethanal
   c) Propanal
   d) Acetaldehyde
2. Which reagent is used to convert an aldehyde into a primary alcohol?
   a) PCC
   b) LiAlH₄
   c) KMnO₄
   d) H₂SO₄
3. Benedict’s solution is used to test the presence of:
   a) Ketone
   b) Aldehyde
   c) Carboxylic acid
   d) Alcohol
4. Which of the following compounds does not give Tollens’ test?
   a) Formaldehyde
   b) Acetaldehyde
   c) Acetone
   d) Benzaldehyde
5. Which of the following is an example of a nucleophilic addition reaction?
   a) Addition of HCN to an aldehyde
   b) Halogenation of alkane
   c) Nitration of benzene
   d) Friedel–Crafts reaction
6. Formaldehyde on oxidation gives:
   a) Methanol
   b) Formic acid
   c) Acetic acid
   d) Carbon dioxide
7. Which reagent converts aldehydes and ketones into alkanes?
   a) LiAlH₄
   b) Clemmensen reagent
   c) PCC
   d) Fehling’s solution
8. Fehling’s solution does not react with:
   a) Formaldehyde
   b) Acetaldehyde
   c) Acetone
   d) Glucose
9. Which compound gives a yellow precipitate with 2,4-DNP reagent?
   a) Ethanol
   b) Propanal
   c) Acetic acid
   d) Methoxyethane
10. The reaction of aldehyde with ammonia derivatives is known as:
    a) Cannizzaro reaction
    b) Aldol condensation
    c) Schiff’s reaction
    d) Wolff–Kishner reduction
11. In the Cannizzaro reaction, the aldehyde must not have:
    a) α-hydrogen
    b) β-hydrogen
    c) Carbonyl group
    d) Oxygen atom
12. Which product is formed when acetone reacts with hydrazine, followed by heating with KOH?
    a) Ethane
    b) Propane
    c) Propene
    d) Methane
13. Aldol condensation occurs in the presence of:
    a) Acid
    b) Base
    c) Light
    d) Peroxide
14. Which of the following reactions is used to prepare aromatic aldehydes?
    a) Cannizzaro reaction
    b) Rosenmund reduction
    c) Clemmensen reduction
    d) Wurtz reaction
15. Formaldehyde polymerizes to form:
    a) Bakelite
    b) Urotropine
    c) Polyformaldehyde
    d) Nylon
16. The IUPAC name of acetone is:
    a) Propanal
    b) Propanone
    c) Butanone
    d) Ethanal
17. Which of the following reagents is used to distinguish between an aldehyde and a ketone?
    a) NaOH
    b) 2,4-DNP
    c) Fehling’s solution
    d) H₂SO₄
18. Which of the following gives a positive iodoform test?
    a) Formaldehyde
    b) Acetaldehyde
    c) Benzaldehyde
    d) Methanol
19. When acetaldehyde reacts with HCN, the product formed is:
    a) Cyanohydrin
    b) Alcohol
    c) Ether
    d) Amine
20. The product obtained when benzaldehyde is oxidized is:
    a) Benzoic acid
    b) Benzyl alcohol
    c) Toluene
    d) Phenol

Answers & Solutions

1. b) Ethanal — CH₃CHO is ethanal.
2. b) LiAlH₄ — Reduces aldehyde to primary alcohol.
3. b) Aldehyde — Benedict’s test detects reducing aldehydes.
4. c) Acetone — Ketones do not give Tollens’ test.
5. a) Addition of HCN — Typical nucleophilic addition reaction.
6. b) Formic acid — Oxidation of formaldehyde gives formic acid.
7. b) Clemmensen reagent — Reduces carbonyl to alkane.
8. c) Acetone — Ketones do not react with Fehling’s solution.
9. b) Propanal — Aldehydes give yellow ppt with 2,4-DNP.
10. c) Schiff’s reaction — Reaction with ammonia derivatives.
11. a) α-hydrogen — Absence of α-H is essential for Cannizzaro reaction.
12. b) Propane — Wolff–Kishner reduction gives hydrocarbon.
13. b) Base — Aldol condensation occurs in basic medium.
14. b) Rosenmund reduction — Converts acid chloride to aldehyde.
15. c) Polyformaldehyde — Polymer of formaldehyde.
16. b) Propanone — IUPAC name of acetone.
17. c) Fehling’s solution — Gives positive test only with aldehyde.
18. b) Acetaldehyde — Only aldehydes with CH₃CO– group give iodoform test.
19. a) Cyanohydrin — Nucleophilic addition of HCN.
20. a) Benzoic acid — Oxidation product of benzaldehyde.