Aldehydes, Ketones and Carboxylic Acids TEXTBOOK Solution

Question 1.

Write the structures of the following compounds.

  1. α-Methoxypropionaldehyde
  2. 3-Hydroxybutanal
  3. 2-Hydroxycyclopentanecarbaldehyde
  4. 4-Oxopentanal
  5. Di-sec.butyl ketone
  6. 4-Fluoroacetophenone

Solution:

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 1

Question 2.

Write the structures of the products of the following reactions :

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 2
Solution:

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 3

Question 3.

Arrange the following compounds in increasing order of their boiling points.
CH3CHO, CH3CH2OH, CH3OCH3, CH3CH2CH3

Solution:

CH3CH2CH3 < CH3OCH3 < CH3CHO < CH3CH2OH

Question 4.

Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions.

  1. Ethanal, Propanal, Propanone, Butanone.
  2. Benzaldehyde, p-Tolualdehyde, p – Nitrobenzaldehyde, Acetophenone.

Hint: Consider steric effect and electronic effect.

Solution:

  1. Butanone < Propanone < Propanal < Ethanal
  2. Acetophenone < p-Tolualdehyde, Benzaldehyde < p-Nitrobenzaldehyde

Question 5.

Predict the products of the following reactions :

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 4

Solution:

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 5

Question 6.

Give the IUPAC names of the following compounds :

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 6

Solution:

  1. 3-Phenylpropanoic acid
  2. 3-Methylbut-2-enoic acid
  3. 2-Methylcyclopentanecarboxylic acid
  4. 2,4,6-Trinitrobenzoic acid

Question 7.

Show how each of the following compounds can be converted to benzoic acid.

  1. Ethylbenzene
  2. Acetophenone
  3. Bromobenzene
  4. Phenylethene (Styrene)

Solution:

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 7
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 8

Question 8.

Which acid of each pair shown here would you expect to be stronger ?

(i) CH3CO2H or CH2FCO2H
(ii) CH2FCO2H or CH2ClCO2H
(iii) CH2FCH2CH2CO2H or CH3CHFCH2CO2H
NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 9

Solution:

(i) H2CFCOOH will be stronger of the two. The presence of electronegative F atom at the α-C causes electron withdrawal from the COOH and facilitates the release of H+.

(ii) CH2FCO2H is a stronger acid for the same reason as stated above. F is more electronegative than Cl, so it withdraws electrons from the carboxyl group to a greater extent.

(iii) CH3CHFCH2COOH is stronger. Although both the givenacidshaveFatomin them, it is the proximity of F in CH3CHFCH2COOH to the COOH group which makes it more acidic.

NCERT Solutions for Class 12 Chemistry Chapter 12 Aldehydes, Ketones and Carboxylic Acids 10