PYQSide ExamsMy practice

Aldehydes, Ketones and Carboxylic Acids · Question 3

RE-NEET (UG) 2026MCQMedium📈 Topic in 25% papers+4−1
1

The compound that CANNOT be obtained from the aldol condensation reaction shown below, is [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]

Answer

(2) [figure]

Solution

In aldol condensation under basic conditions, elimination of water occurs via the E1cb pathway through an enolate intermediate adjacent to the carbonyl group.

Cross-aldol reaction between 2,2-dimethylcyclopentanone and benzaldehyde gives, after dehydration, the conjugated benzylidene enone, obtained as its two geometrical isomers (1) and (3).

Self-aldol condensation followed by dehydration towards the -position gives conjugated enone (4).

Compound (2) requires dehydration into the non-enolisable, unconjugated ring position, which cannot proceed via E1cb and lacks conjugation stability. Hence, (2) cannot be obtained.

Answer: (2)

RE-NEET (UG) 2026

Keep practising — Aldehydes, Ketones and Carboxylic Acids

2

For the following reaction sequence, choose the correct option [figure]

  1. Both P and Q are carbonyl compounds
  2. If P is the sodium salt of a carboxylic acid, Q is a primary alcohol
  3. P and Q are aromatic compounds
  4. If P gives a carboxylic acid on acidification, Q gives a poisonous gas on exposure to air and light
RE-NEET (UG) 2026
3

Identify the suitable reagent for the following conversion. [figure]

  1. (i) NaBH4, (ii) H+/H2O
  2. H2/Pd-BaSO4
  3. (i) LiAlH4, (ii) H+/H2O
  4. (i) AlH(iBu)2, (ii) H2O
NEET (UG) 2025
4

The correct order of decreasing acidity of the following aliphatic acids is

  1. HCOOH > CH3COOH > (CH3)2CHCOOH > (CH3)3CCOOH
  2. HCOOH > (CH3)3CCOOH > (CH3)2CHCOOH > CH3COOH
  3. (CH3)3CCOOH > (CH3)2CHCOOH > CH3COOH > HCOOH
  4. CH3COOH > (CH3)2CHCOOH > (CH3)3CCOOH > HCOOH
NEET (UG) 2025
5

The major product of the following reaction is [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2025
6

Match List-I with List-II and choose the correct option.

  1. A-II, B-IV, C-I, D-III
  2. A-I, B-II, C-III, D-IV
  3. A-IV, B-III, C-II, D-I
  4. A-II, B-I, C-IV, D-III
NEET (UG) 2024
7

Identify the correct reagents that would bring about the following transformation. [figure]

  1. (i) H2O/H+, (ii) CrO3
  2. (i) BH3, (ii) H2O2/OH , (iii) PCC
  3. (i) BH3, (ii) H2O2/OH , (iii) alk. KMnO4
  4. (i) H2O/H+, (ii) PCC
NEET (UG) 2024
8

Fehling's solution 'A' is

  1. aqueous copper sulphate
  2. alkaline copper sulphate
  3. alkaline solution of sodium potassium tartrate (Rochelle's salt)
  4. aqueous sodium citrate
NEET (UG) 2024
9

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

  1. A-IV, B-I, C-III, D-II
  2. A-III, B-I, C-II, D-IV
  3. A-IV, B-I, C-II, D-III
  4. A-I, B-IV, C-II, D-III
NEET (UG) 2024
10

Select the incorrect reaction among the following :

  1. CH3COCl [ ]H2O CH3COOH
  2. [figure]
  3. CH3CH2OH [(ii) H3O ](i) KMnO4/OH- CH3COOH
  4. CH3CH2CH2OH CrO3-H2SO4 CH3CH2COOH
RE-NEET (UG) 2024
11

Identify product (A) in the following reaction : [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2023

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 NEET Chemistry chapters