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Aldehydes, Ketones and Carboxylic Acids · Question 30

NEET 2018MCQMedium📈 Topic in 12% papers+4−1
1

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

Answer

(3) [figure] and I2

Solution

NaOI is formed from iodine and alkali: I2 + 2NaOH NaOI + NaI + H2O ⇒ Y = I2.

The yellow precipitate with a characteristic smell is iodoform, CHI3.

As per NCERT, the iodoform test is given by compounds with a CH3CO- group or a CH3CH(OH)- group (which NaOI oxidises to CH3CO-).

Only 1-phenylethanol, C6H5CH(OH)CH3 ( C8H10O), has the CH3CH(OH)- group:

C6H5CH(OH)CH3 NaOI C6H5COCH3 NaOI C6H5COONa + CHI3

Answer: (3)

NEET 2018

Keep practising — Aldehydes, Ketones and Carboxylic Acids

2

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
3

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
4

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
5

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)
6

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)
7

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)
8

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

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET 2016 (Phase 2)
9

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
10

Which one of the following esters gets hydrolysed most easily under alkaline conditions?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
AIPMT 2015
11

Treatment of cyclopentanone [figure] with methyl lithium gives which of the following species ?

  1. Cyclopentanonyl radical
  2. Cyclopentanonyl biradical
  3. Cyclopentanonyl anion
  4. Cyclopentanonyl cation
AIPMT 2015 (Cancelled)

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