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Aldehydes, Ketones and Carboxylic Acids · Question 28

NEET (UG) 2020MCQEasy📈 Topic in 25% papers+4−1
1

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

Answer

(3) Cross Aldol condensation

Solution

Acetophenone has -hydrogens; benzaldehyde has none. With dilute alkali, the carbanion from acetophenone adds to benzaldehyde and the product dehydrates.

C6H5CHO + CH3COC6H5 dil. NaOH C6H5CH=CHCOC6H5 + H2O

As per NCERT, aldol condensation between two different carbonyl compounds is called cross aldol condensation (this case is also known as Claisen–Schmidt condensation).

Answer: (3)

NEET (UG) 2020

Keep practising — Aldehydes, Ketones and Carboxylic Acids

2

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

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

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
4

Carboxylic acids have higher boiling points than aldehydes, ketones and even alcohols of comparable molecular mass. It is due to their

  1. formation of intramolecular H-bonding
  2. formation of carboxylate ion
  3. more extensive association of carboxylic acid via van der Waals' forces of attraction
  4. formation of intermolecular H-bonding
NEET 2018
5

Of the following, which is the product formed when cyclohexanone undergoes aldol condensation followed by heating?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET 2017
6

Consider the reactions, [figure] Identify A, X, Y and Z.

  1. A-Methoxymethane, X-Ethanol, Y-Ethanoic acid, Z-Semicarbazide.
  2. A-Ethanal, X-Ethanol, Y-But-2-enal, Z-Semicarbazone.
  3. A-Ethanol, X-Acetaldehyde, Y-Butanone, Z-Hydrazone.
  4. A-Methoxymethane, X-Ethanoic acid, Y-Acetate ion, Z-Hydrazine.
NEET 2017
7

Which of the following reagents would distinguish cis-cyclopentane-1,2-diol from the trans-isomer?

  1. MnO2
  2. Aluminium isopropoxide
  3. Acetone
  4. Ozone
NEET 2016 (Phase 1)
8

The product formed by the reaction of an aldehyde with a primary amine is

  1. carboxylic acid
  2. aromatic acid
  3. Schiff's base
  4. ketone
NEET 2016 (Phase 1)
9

The correct order of the strengths of the carboxylic acids [figure] is

  1. I > II > III
  2. II > III > I
  3. III > II > I
  4. II > I > III
NEET 2016 (Phase 2)
10

The correct structure of the product 'A' formed in the reaction [figure]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET 2016 (Phase 2)
11

Reaction of a carbonyl compound with one of the following reagents involves nucleophilic addition followed by elimination of water. The reagent is

  1. hydrazine in presence of feebly acidic solution
  2. hydrocyanic acid
  3. sodium hydrogen sulphate
  4. a Grignard reagent.
AIPMT 2015

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