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Aldehydes, Ketones and Carboxylic Acids · Question 20

NEET (UG) 2022 (Phase 2)MCQEasy📈 Topic in 38% papers+4−1
1

Which of the following reactions is not an example for nucleophilic addition-elimination reaction?

  1. CH3CHO + NH3 CH3CH=NH + H2O
  2. CH3CHO + NaHSO3 CH3- H | OH |C-SO3Na
  3. CH3CHO + NH2OH CH3CH=N-OH + H2O
  4. CH3CHO + C6H5NHNH2 CH3CH=N-NHC6H5 + H2O

Answer

(2) CH3CHO + NaHSO3 CH3- H | OH |C-SO3Na

Solution

As per NCERT, ammonia and its derivatives (H2N-Z) add to the carbonyl group and the adduct then loses a water molecule; this is an addition–elimination reaction, giving imines, oximes, hydrazones etc. Reactions (1), (3) and (4) belong to this type (H2O is eliminated).

In (2), sodium hydrogensulphite simply adds to the carbonyl group to form the crystalline bisulphite addition compound; nothing is eliminated it is only a nucleophilic addition reaction.

Answer: (2)

NEET (UG) 2022 (Phase 2)

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2

The product formed from the following reaction sequence is [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2022 (Phase 2)
3

The products A and B in the following reaction sequence are : [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2022 (Phase 2)
4

The incorrect method to synthesize benzaldehyde is

  1. [figure] , CH3MgBr, followed by H3O+
  2. [figure] , H2, Pd-BaSO4
  3. [figure] , DIBAL-H, followed by H2O
  4. [figure] , CrO2Cl2 in CS2, followed by H3O+
NEET (UG) 2022 (Phase 2)
5

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

  1. (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
  2. (a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)
  3. (a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)
  4. (a)-(i), (b)-(iv), (c)-(iii), (d)-(ii)
NEET (UG) 2021
6

The intermediate compound 'X' in the following chemical reaction is : [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
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7

The product formed in the following chemical reaction is : [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2021
8

Identify compound X in the following sequence of reactions : [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2020
9

Reaction between benzaldehyde and acetophenone in presence of dilute NaOH is known as :

  1. Cannizzaro's reaction
  2. Cross Cannizzaro's reaction
  3. Cross Aldol condensation
  4. Aldol condensation
NEET (UG) 2020
10

The major product of the following reaction is : [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2019
11

Compound A, C8H10O, is found to react with NaOI (produced by reacting Y with NaOH) and yields a yellow precipitate with characteristic smell. A and Y are respectively

  1. [figure] and I2
  2. [figure] and I2
  3. [figure] and I2
  4. [figure] and I2
NEET 2018

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