Alcohols, Phenols and Ehers TEXTBOOK Solution

Question 1.

Classify the following as primary, secondary and tertiary alcohols :

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 1

Solution:

Primary alcohols : (i), (ii) and (iii)
Secondary alcohols : (iv) and (v)
Tertiary alcohols : (vi)

Question 2.

Identify allylic alcohols in the above examples.

Solution:

Allvlir alcohols : (ii) and (vi).

Question 3.

Name the following compounds according to IUPAC system.

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 2
NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 3

Solution:

  1. 3-Chloromethyl-2-isopropylpentan-l-ol
  2. 2, 5-Dimethylhexane-1,3-diol
  3. 3-Bromocyclohexanol
  4. Hex-l-en-3-ol
  5. 2-Bromo-3-methylbut-2-en-1 -ol

Question 4.

Show how are the following alcohols prepared by the reaction of a suitable Grignard reagent on methanal.

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 4
Solution:

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 5

Question 5.

Write structures of the products of the following reactions :

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 6

Solution:

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 8

Question 6.

Give structures of the products you would expect when each of the following alcohol reacts with (a) HCl – ZnCl2 (b) HBr and (c) SOCl2.

  1.  Butan-1-ol
  2. 2-Methylbutan-2-ol

Solution:

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 9

Question 7.

Predict the major product of acid catalysed dehydration of

  1. 1-methylcyclohexanol and
  2. butan-1-ol

Solution:

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 10

Question 8.

Ortho and para nitrophenols are more acidic than phenol. Draw the resonance structures of the corresponding phenoxide ions.

Solution:

The attachment of the -NO2 group to the phenol molecule at 0- and p-positions decreases the electron density on oxygen atom. This causes the oxygen atom to pull the bond pair of electrons of the O – H bond towards itself thereby facilitating the release of H as H+.

The resonance structures of the phenoxide ions are :

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 11
NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 12

Question 9.

Write the equations involved in the following reactions :

  1. Reimer-Tiemann reaction
  2. Kolbe’s reaction

Solution:

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 13

Question 10.

Write the reactions of Williamson synthesis of 2-ethoxy-3-methylpentane starting from ethanol and 3-methylpentan-2-ol.

Solution:

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 14

Question 11.

Which of the following is an appropriate set of reactants for the preparation of 1 -methoxy-4- nitrobenzene and why?

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 15

Solution:

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 16

Question 12.

Predict the products of the following reactions :

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 17

Solution:

NCERT Solutions for Class 12 Chemistry Chapter 11 Alcohols, Phenols and Ehers 18