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Aldehydes, Ketones and Carboxylic Acids · Question 6

JEE Main 2026 (Online) 5th April Evening ShiftMCQMedium📈 Topic in 10% papers+4−1
1

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

Answer

(4) Statement I is false but Statement II is true

Solution

Statement I: In semicarbazide, the -NH2 attached to C=O is an amide nitrogen – its lone pair is delocalised into C=O, so it is not nucleophilic. The free -NH2 on the other N attacks the carbonyl carbon:

CH3-CH=O + H2N- H |N- O \|C-NH2 H+

CH3-CH=N- H |N- O \|C-NH2 + H2O (acetaldehyde semicarbazone)

⇒ the product given in Statement I (C=N bonded directly to C=O) is wrong ∴ Statement I is false.

Statement II: Ph-CH(OH)(OCH3) is a hemiacetal; in dilute acid it is hydrolysed back to the aldehyde and alcohol:

Ph-CH(OH)(OCH3) H3O+ Ph-CH=O + CH3OH

∴ Statement II is true.

Answer: (4)

JEE Main 2026 (Online) 5th April Evening Shift

Keep practising — Aldehydes, Ketones and Carboxylic Acids

2

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
3

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
4

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
5

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
6

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
7

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
8

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
9

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
10

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
11

'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

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