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Aldehydes, Ketones and Carboxylic Acids · Question 3

JEE Main 2026 (Online) 6th April Evening ShiftMCQMedium📈 Topic in 32% papers+4−1
1

'x' is the product which is obtained by the hydrolysis of prop-1-yne in the presence of mercuric sulphate under dilute acidic medium at 333 K. 'y' is the product which is obtained by the reaction of ethane nitrile with methyl magnesium bromide in dry ether followed by hydrolysis. IUPAC name of product obtained from 'x' and 'y' in the presence of barium hydroxide followed by heating is :

  1. 2-Methylpent-4-en-3-one
  2. 4-Methylpent-3-en-2-one
  3. 4-Methylpent-1-ene
  4. 2-Methylpent-3-one

Answer

(2) 4-Methylpent-3-en-2-one

Solution

x: CH3-C CH + H2O [333 K]Hg2+, dil. H2SO4 CH3COCH3 (acetone, Markovnikov hydration)

y: CH3-C N + CH3MgBr dry ether (CH3)2C=NMgBr H3O+ CH3COCH3 (acetone)

So x and y are both acetone. With Ba(OH)2 acetone undergoes aldol reaction; heating dehydrates the aldol:

2CH3COCH3 Ba(OH)2 (CH3)2C(OH)CH2COCH3 [-H2O] (CH3)2C=CH-CO-CH3

Numbering from the end nearer to C=O: 5CH3- 4C(CH3)= 3CH- 2CO- 1CH3

∴ 4-Methylpent-3-en-2-one (mesityl oxide)

Answer: (2)

JEE Main 2026 (Online) 6th April Evening Shift

Keep practising — Aldehydes, Ketones and Carboxylic Acids

2

" P " is a hydrocarbon of molecular formula:- C8H14. On ozonolysis, " P " forms "Q". "Q" on treatment with alkali under reflux condition produces "R", which on treatment with I2/NaOH gives a yellow precipitate. Acidification of the solution gives "S". The structure of "S" is given below:- [figure] The correct structure of P is

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 5th April Morning Shift
3

Complete the following reaction sequence and give the name of major product 'P'. [figure]

  1. 2-Chloropropanoic acid
  2. 3-Chloropropanoic acid
  3. 1-Chloropropane
  4. 2-Chloropropane
JEE Main 2026 (Online) 5th April Evening Shift
4

Given below are two statements: In the light of the above statements, choose the correct answer from the options given below:

  1. Both Statement I and Statement II are true
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true
JEE Main 2026 (Online) 5th April Evening Shift
5

Consider the following sequence of reactions to give the major product (X) [figure] P g of the major product (X) formed is reacted with NaHCO3 solution to liberate a gas which occupied 11.2 dm3 at STP. P = g. (Given molar mass in g mol-1 H : 1, C : 12, O : 16, Cl : 35.5)

JEE Main 2026 (Online) 4th April Morning Shift
6

An organic compound “x” where molar ratio of C, O and H are equal, on treatment with 50% KOH under reflux followed by acidification produced “y”. The most likely structure of “y” is: [Molar mass of ‘x’ is 58 g mol-1]

  1. [figure]
  2. CH3-CH=CH-CH=O
  3. [figure]
  4. [figure]
JEE Main 2026 (Online) 2nd April Evening Shift
7

A molecule (X) with following structure under mild acidic condition is hydrolysed to produce (Y) and (Z). Identify the correct statements about (Y) and (Z). [figure] Choose the correct answer from the options given below :

  1. A, B and C Only
  2. B and C Only
  3. C and D Only
  4. A and D Only
JEE Main 2026 (Online) 2nd April Evening Shift
8

Given below are the four isomeric compounds (P, Q, R, S) [figure] Identify correct statements from below. Choose the correct option.

  1. C and E only
  2. A and E only
  3. A, B, D and E only
  4. A, C and E only
JEE Main 2026 (Online) 28th January Morning Shift
9

The correct order of acidic strength of the major products formed in the given reactions, is : Choose the correct answer from the options given below :

  1. C > A > D > B
  2. A > D > C > B
  3. A > D > B > C
  4. C > B > A > D
JEE Main 2026 (Online) 28th January Evening Shift
10

A student is given one compound among the following compounds that gives positive test with Tollens' reagent. [figure] The compound is :

  1. B
  2. D
  3. A
  4. C
JEE Main 2026 (Online) 24th January Morning Shift
11

The unsaturated ether on acidic hydrolysis produces carbonyl compounds as shown below :- [figure] Based on this, predict the solution/reagent that will help to distinguish "P" and "Q" obtained in the following reaction :- CH3-CH=CH-O- CH3 |C=CH2 [ ]H3O P + Q

  1. Saturated NaHSO3 solution
  2. Fehling solution
  3. Lucas reagent
  4. 2,4-DNP reagent
JEE Main 2026 (Online) 24th January Evening Shift

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Organic ChemistryOrganic Chemistry – Some Basic Principles and TechniquesIsomerismHydrocarbonsHaloalkanes and HaloarenesAlcohols, Phenols and EthersAldehydes, Ketones and Carboxylic AcidsAminesBiomoleculesPrinciples Related to Practical Chemistry