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Aldehydes, Ketones and Carboxylic Acids

JEE Main 2026 (Online) 22nd January Evening ShiftMCQMedium📈 Topic in 11% papers+4−1
Ques. 1JEE Main 2026, 22 January (Evening Shift)

The compound A, C8H8O2 reacts with acetophenone to form a single product via cross-Aldol condensation. The compound A on reaction with conc. NaOH forms a substituted benzyl alcohol as one of the two products. The compound A is :

  1. 2-hydroxy acetophenone
  2. 4-hydroxy benzaldehyde
  3. 4-methyl benzoic acid
  4. 4-methoxy benzaldehyde

Answer

(4) 4-methoxy benzaldehyde

Solution

A with conc. NaOH gives a substituted benzyl alcohol and a carboxylate (Cannizzaro reaction) A is an aromatic aldehyde with no α-hydrogen.

A has no α-hydrogen, only acetophenone forms the enolate in the cross-aldol (Claisen–Schmidt) reaction a single product.

4-Methoxybenzaldehyde, CH3O-C6H4-CHO = C8H8O2, fits both.

Other options: 2-hydroxyacetophenone is a ketone (no Cannizzaro reaction); 4-hydroxybenzaldehyde is C7H6O2; 4-methylbenzoic acid is an acid, not an aldehyde.

Cannizzaro: 2 CH3OC6H4CHO conc. NaOH CH3OC6H4CH2OH + CH3OC6H4COONa

Cross-aldol: CH3OC6H4CHO + C6H5COCH3 OH- CH3OC6H4CH=CHCOC6H5 + H2O

Answer: (4)

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Ques. 2JEE Main 2026, 21 January (Morning Shift)

An organic compound "P" of molecular formula C6H12O3 gives positive iodoform test but negative Tollens' test. When "P" is treated with dilute acid, it produces "Q". "Q" gives positive Tollens' test and also iodoform test. The structure of "P" is :

  1. H- O \|C-CH2-CH2- OCH3 |CH-OCH3
  2. CH3- O \|C- OCH3 |CH- OCH3 |CH2
  3. CH3- O \|C-CH2- OCH3 |CH-OCH3
  4. CH3- O \|C- OCH3 | OCH3 |C-CH3
Ques. 3JEE Main 2026, 21 January (Evening Shift)

Match List - I with List - II. Choose the correct answer from the options given below :

  1. A-II, B-III, C-IV, D-I
  2. A-IV, B-III, C-I, D-II
  3. A-IV, B-I, C-II, D-III
  4. A-II, B-IV, C-I, D-III
Ques. 4JEE Main 2025, 8 April (Evening Shift)

A [(ii) H3O+](i) NaOH B [(ii) H2SO4, ](i) EtOH C 'A' shows positive Lassaigne's test for N and its molar mass is 121. 'B' gives effervescence with aq NaHCO3. 'C' gives fruity smell. Identify A, B and C from the following.

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 5JEE Main 2025, 8 April (Evening Shift)

When [figure] undergoes intramolecular aldol condensation, the major product formed is :

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 6JEE Main 2025, 7 April (Morning Shift)

Which of the following compounds is least likely to give effervescence of CO2 in presence of aq. NaHCO3?

  1. Ph- NH3 Cl
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 7JEE Main 2025, 7 April (Evening Shift)

"P" is an optically active compound with molecular formula C6H12O. When "P" is treated with 2,4-dinitrophenylhydrazine, it gives a positive test. However, in presence of Tollens' reagent, "P" gives a negative test. Predict the structure of "P".

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 8JEE Main 2025, 4 April (Morning Shift)

Aldol condensation is a popular and classical method to prepare , -unsaturated carbonyl compounds. This reaction can be both intermolecular and intramolecular. Predict which one of the following is not a product of intramolecular aldol condensation?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
Ques. 9JEE Main 2025, 4 April (Evening Shift)

Which among the following compounds give yellow solid when reacted with NaOI/NaOH? Choose the correct answer from the options given below :

  1. (A) and (C) Only
  2. (C) and (D) Only
  3. (B), (C) and (E) Only
  4. (A), (C) and (D) Only
Ques. 10JEE Main 2025, 3 April (Morning Shift)

Number of molecules from below which cannot give iodoform reaction is : Ethanol, Isopropyl alcohol, Bromoacetone, 2-Butanol, 2-Butanone, Butanal, 2-Pentanone, 3-Pentanone, Pentanal and 3-Pentanol.

  1. 4
  2. 3
  3. 5
  4. 2
Ques. 11JEE Main 2025, 3 April (Evening Shift)

The major product (P) in the following reaction is : Ph- O \|C- O \|C-H [ ]KOH Major ProductP

  1. Ph- O \|C-COO K
  2. Ph- OH |CH-CH2OH
  3. Ph- OH |CH-COO K
  4. Ph- O \|C-CH2OH

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