PYQSide ExamsMy practice

Aldehydes, Ketones and Carboxylic Acids · Question 15

JEE Advanced 2024 Paper 2NumericalHard📈 Topic in 17% papers+4
1

Sum of number of oxygen atoms in S and T is .

Answer

2

Solution

P ( C9H18O2, DBE = 1): one C=C (decolorises Br2 water) + two –OH; iodoform +, so a CH3CH(OH)- unit. S and T come from PCC oxidation then heating (decarboxylation), so Q and R are β-hydroxy acids.

[figure] (P) [(ii) H2O2](i) O3 [figure] (Q) + [figure] (R)

Oxidative ozonolysis cuts the C=C and turns each =CH– into –COOH. Q has CH3CH(OH)- (iodoform +); R does not (iodoform –).

[figure] PCC [figure] [-CO2] [figure] (S)

PCC oxidises the 2° alcohol to a ketone; the β-keto acid loses CO₂ on heating. S = acetone (iodoform +).

[figure] PCC [figure] [-CO2] [figure] (T)

Same two steps; T = butan-2-one, a methyl ketone (iodoform +).

O atoms: S = 1, T = 1; sum = 2

Answer: 2

JEE Advanced 2024 Paper 2

Keep practising — Aldehydes, Ketones and Carboxylic Acids

2

The List-II contains products obtained from the reaction of compounds in List-I with O3/Zn-H2O followed by cyclization (via more stable enolate) in the presence of aqueous NaOH. Match each entry in List-I with appropriate entry in List-II and choose the correct option.

  1. P ⟶ 2; Q ⟶ 4; R ⟶ 1; S ⟶ 3
  2. P ⟶ 3; Q ⟶ 4; R ⟶ 5; S ⟶ 2
  3. P ⟶ 2; Q ⟶ 1; R ⟶ 5; S ⟶ 3
  4. P ⟶ 3; Q ⟶ 5; R ⟶ 4; S ⟶ 2
JEE Advanced 2026 Paper 1
3

Match the major products obtained in the reactions given in List-I with the corresponding structures in List-II and choose the correct option.

  1. P → 2; Q ⟶ 1; R → 5; S ⟶ 4
  2. P → 1; Q ⟶ 2; R → 4; S ⟶ 5
  3. P → 1; Q ⟶ 2; R → 3; S ⟶ 4
  4. P → 2; Q ⟶ 1; R → 3; S ⟶ 5
JEE Advanced 2026 Paper 1
4

Considering LiBH4 reduces an ester group to the corresponding alcohol and does not reduce a carboxylic acid group, the correct statement about the major products P, Q, R and S is [figure]

  1. P & Q are identical, and R & S are diastereomers.
  2. P & Q are diastereomers, and R & S are identical.
  3. P & Q are diastereomers, and R & S are diastereomers.
  4. P & Q are identical, and R & S are identical.
JEE Advanced 2026 Paper 1
5

In the following reaction sequence, Q, R, S and T are the major products. [figure] The correct statement(s) about Q, R, S and T is(are)

  1. S on warming with ammoniacal AgNO3 results in the formation of silver mirror.
  2. Q on treatment with Cl2(excess)/UV gives gammaxane.
  3. T is a heterocyclic compound.
  4. R on acid catalyzed intramolecular cyclization followed by treatment with Zn-Hg/HCl gives 9,10-dihydroxyanthracene.
JEE Advanced 2026 Paper 1
6

The sum of total number of carbonyl groups ( >C=O ) present in the major products X and Y in the following reactions is . [figure]

JEE Advanced 2026 Paper 1
7

Natural rubber on complete ozonolysis ( O3/Zn-H2O) gives compound X as the major product. X gives positive iodoform and Tollen's tests. X on heating with aqueous NaOH gives Y as the major product. Y is

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Advanced 2026 Paper 2
8

The reaction sequence given below is carried out with 16 moles of X. The yield of the major product in each step is given below the product in parentheses. The amount (in grams) of S produced is. [figure] Use: Atomic mass (in amu): H = 1, C = 12, O = 16, Br = 80

JEE Advanced 2025 Paper 1
9

The correct reaction/reaction sequence that would produce a dicarboxylic acid as the major product is

  1. [figure] [ (iii) H3O+] (i) NaCN; (ii) HO-, H2O
  2. arraycCHO\ |\ (CHOH)4\ |\ CH2OH array Br2, H2O
  3. [figure] [(ii) KMnO4, H2SO4, ](i) KOH, EtOH
  4. [figure] H2CrO4
JEE Advanced 2025 Paper 2
10

Monocyclic compounds P, Q, R and S are the major products formed in the reaction sequences given below. [figure] The product having the highest number of unsaturated carbon atom(s) is

  1. P
  2. Q
  3. R
  4. S
JEE Advanced 2025 Paper 2
11

Reaction of iso-propylbenzene with O2 followed by the treatment with H3O+ forms phenol and a by-product P. Reaction of P with 3 equivalents of Cl2 gives compound Q. Treatment of Q with Ca(OH)2 produces compound R and calcium salt S. The correct statement(s) regarding P, Q, R and S is(are)

  1. Reaction of P with R in the presence of KOH followed by acidification gives [figure]
  2. Reaction of R with O2 in the presence of light gives phosgene gas
  3. Q reacts with aqueous NaOH to produce Cl3CCH2OH and Cl3CCOONa
  4. S on heating gives P
JEE Advanced 2024 Paper 1

All Aldehydes, Ketones and Carboxylic Acids PYQs →

PDFDownload Aldehydes, Ketones and Carboxylic Acids PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All JEE Advanced Chemistry chapters