PYQSide ExamsMy practice

Aldehydes, Ketones and Carboxylic Acids · Question 8

JEE Main 2026 (Online) 2nd April Evening ShiftMCQMedium📈 Topic in 10% papers+4−1
1

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]

Answer

(3) [figure]

Solution

C : H : O = 1 : 1 : 1 ⇒ empirical formula CHO (formula mass 29).

n = 5829 = 2 ⇒ molecular formula C2H2O2 = OHC–CHO (glyoxal).

Glyoxal has no α-hydrogen ⇒ with concentrated (50%) KOH it undergoes Cannizzaro reaction; one CHO is oxidised and the other reduced in the same molecule (intramolecular):

OHC-CHO 50\% KOH, HO-CH2-COO K H3O HO-CH2-COOH

∴ y = glycolic acid (2-hydroxyethanoic acid).

Answer: (3)

JEE Main 2026 (Online) 2nd April Evening Shift

Keep practising — Aldehydes, Ketones and Carboxylic Acids

2

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
3

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
4

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
5

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
6

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
7

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

  1. Statement I is true but Statement II is false
  2. Both Statement I and Statement II are false
  3. Both Statement I and Statement II are true
  4. Statement I is false but Statement II is true
JEE Main 2026 (Online) 24th January Evening Shift
8

Grignard reagent RMgBr (P) reacts with water and forms a gas (Q). One gram of Q occupies 1.4 dm3 at STP. (P) on reaction with dry ice in dry ether followed by H3O+ forms a compound (Z). 0.1 mole of (Z) will weigh g. (Nearest integer)

JEE Main 2026 (Online) 24th January Evening Shift
9

'x' is the product which is obtained from propanenitrile and stannous chloride in the presence of hydrochloric acid followed by hydrolysis. 'y' is the product which is obtained from the but-2-ene by the ozonolysis followed by hydrolysis. From the following, which product is not obtained when one mole of 'x' and one mole of 'y' react with each other in the presence of alkali followed by heating?

  1. 2-Methylpent-2-enal
  2. 2-Methylbut-2-enal
  3. 3-Methylbut-2-enal
  4. Pent-2-enal
JEE Main 2026 (Online) 23rd January Morning Shift
10

[figure] The correct sequence of reagents for the above conversion of X to Y is :

  1. (i) NaOH(aq), (ii) Jones reagent, (iii) H3O+
  2. (i) NaOEt, (ii) B2H6/H2O2, (iii) Jones reagent
  3. (i) Jones reagent, (ii) NaOEt, (iii) Hot KMnO4/KOH
  4. (i) B2H6/H2O2, (ii) NaOEt, (iii) Jones reagent
JEE Main 2026 (Online) 23rd January Morning Shift
11

Which of the following statements are TRUE about Haloform reaction? Choose the correct answer from the options given below :

  1. A, B & C Only
  2. A, C & E Only
  3. B, D & E Only
  4. A & C Only
JEE Main 2026 (Online) 23rd January Evening Shift

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 Main Chemistry chapters