CBSE Class 12 Chemistry Chapter 11: Alcohols, Phenols and Ethers - NCERT Solutions

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NCERT Solutions PDF Class 12 PDF

This chapter provides comprehensive NCERT Solutions for Class 12 Chemistry, focusing on Alcohols, Phenols, and Ethers (Chapter 11). The solutions cover essential topics such as understanding and writing IUPAC names for various organic compounds, including alcohols, phenols, and ethers, and drawing the corresponding chemical structures based on their IUPAC nomenclature. Students will find step-by-step explanations that clarify the principles of organic nomenclature. These solutions are designed to aid students in mastering the concepts and preparing effectively for their board examinations by offering clear and accurate answers to the textbook exercises.

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BoardCBSE
ClassClass 12
SubjectChemiry
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 11: Alcohols, Phenols and Ethers - NCERT Exercises Solutions

Chapter summary

Chapter 11 of the NCERT Class 12 Chemistry textbook deals with Alcohols, Phenols, and Ethers. The provided NCERT Solutions focus on reinforcing the understanding of IUPAC nomenclature for these functional groups. Students will practice naming complex structures and drawing structures from given names, ensuring a solid grasp of organic naming conventions essential for this topic.

Learning outcomes

  • Understand the principles of IUPAC nomenclature for alcohols, phenols, and ethers.
  • Write the IUPAC names for given structures of alcohols, phenols, and ethers.
  • Draw the chemical structures corresponding to given IUPAC names.
  • Identify and name functional groups within organic molecules.
  • Apply nomenclature rules to branched and substituted compounds.

Topics covered

Paper topics

  • IUPAC Nomenclature of Alcohols
  • IUPAC Nomenclature of Phenols
  • IUPAC Nomenclature of Ethers
  • Structure Drawing from IUPAC Names
  • Identification of Functional Groups
  • Branched Alcohols
  • Substituted Phenols
  • Mixed Ethers
  • Alcohols with Multiple Hydroxyl Groups
  • Aromatic Ethers

Important topics

  • IUPAC Nomenclature of Alcohols
  • IUPAC Nomenclature of Phenols
  • IUPAC Nomenclature of Ethers
  • Structure Drawing from IUPAC Names
  • Numbering of Carbon Chains
  • Locant Assignment

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Questions and Solutions

Question 11.1

Write the IUPAC names of the following compounds:

  1. CH3 CH_3 CH- CH. CH3

    CH_3 OH CH_3

  2. H_3C—CH—CH_2—CH—CH—CH_2—CH_3

    OH OH C_2H_5

  3. CH3— CH — - CH—CH3

    OH OH

  4. HO - CH_2 - CH - CH_2 - OH OH

  5. CH_3 OH

  6. CH3

  7. CH3 OH CH;

  8. CH3 HO. CH3

  9. CH_3

    -СН₂— ÇН — СН₃ -0- CH3

  10. C_6H_5 - O - C_2H_5

  11. C_6H_5 - O - C_7H_{15}(n-)

  12. CH_3 - CH_2 - O - CH - CH_2 - CH_3 CH3

Solution:

  1. The longest carbon chain containing the hydroxyl group has 5 carbons. There are two methyl groups attached to carbon 2 and one methyl group attached to carbon 4. The hydroxyl group is on carbon 3. Therefore, the IUPAC name is 2,2,4-Trimethylpentan-3-ol.

  2. The longest carbon chain has 7 carbons. There are two hydroxyl groups on carbons 2 and 4, and an ethyl group on carbon 5. The IUPAC name is 5-Ethylheptane-2,4-diol.

  3. The longest carbon chain has 4 carbons. There are two hydroxyl groups on carbons 2 and 3. The IUPAC name is Butane-2,3-diol.

  4. The longest carbon chain has 3 carbons. There are three hydroxyl groups, one on each carbon. The IUPAC name is Propane-1,2,3-triol.

  5. This is a phenol derivative. The hydroxyl group is attached to the benzene ring. A methyl group is attached to the carbon atom at position 2 relative to the hydroxyl group. The IUPAC name is 2-Methylphenol.

  6. This is a phenol derivative. The hydroxyl group is attached to the benzene ring. A methyl group is attached to the carbon atom at position 4 relative to the hydroxyl group. The IUPAC name is 4-Methylphenol.

  7. This is a phenol derivative. The hydroxyl group is attached to the benzene ring. There are two methyl groups attached to the carbon atoms at positions 2 and 5 relative to the hydroxyl group. The IUPAC name is 2,5-Dimethylphenol.

  8. This is a phenol derivative. The hydroxyl group is attached to the benzene ring. There are two methyl groups attached to the carbon atoms at positions 2 and 6 relative to the hydroxyl group. The IUPAC name is 2,6-Dimethylphenol.

  9. This is an ether. The longest carbon chain is propane. A methoxy group (-OCH3) is attached to carbon 1, and a methyl group is attached to carbon 2. The IUPAC name is 1-Methoxy-2-methylpropane.

  10. This is an ether where a phenyl group (C6H5) is attached to an oxygen atom, which is further attached to an ethyl group (C2H5). The IUPAC name is Ethoxybenzene.

  11. This is an ether. The phenyl group (C6H5) is attached to the oxygen atom, which is attached to a heptyl chain (C7H15). The IUPAC name is 1-Phenoxyheptane.

  12. This is an ether. An ethyl group (CH3CH2-) is attached to the oxygen, and a sec-butyl group (-CH(CH3)CH2CH3) is attached to the other side of the oxygen. The IUPAC name is 2-Ethoxybutane.

Question 11.2

Write structures of the compounds whose IUPAC names are as follows:
  1. 2-Methylbutan-2-ol
Solution:

  1. The name '2-Methylbutan-2-ol' indicates a 4-carbon chain (butan-) with a hydroxyl group (-ol) on the second carbon and a methyl group (-methyl) also on the second carbon. The structure is drawn by first creating a 4-carbon chain, adding an -OH group to the second carbon, and then adding a -CH3 group to the same second carbon.

    CH_3 - C(OH)(CH_3) - CH_2 - CH_3

Common mistakes

  • Incorrectly identifying the parent carbon chain.
  • Errors in numbering the carbon chain to give the lowest locant number to the functional group.
  • Misapplication of prefixes like 'di', 'tri', 'iso', 'neo'.
  • Confusing similar-looking structures or names.
  • Incorrectly placing substituents or functional groups in the drawn structure.

Revision tips

  • Practice drawing structures for each IUPAC name provided.
  • Create flashcards with IUPAC names on one side and structures on the other.
  • Review the rules for numbering the carbon chain and assigning locants.
  • Focus on identifying the principal functional group and the longest carbon chain.
  • Work through the exercises multiple times to build speed and accuracy.

Practice MCQs

Q1. What is the IUPAC name for the compound with the structure CH3-CH(OH)-CH(OH)-CH2-CH3?

Q2. Which IUPAC name corresponds to the structure C6H5-O-C2H5?

Q3. The IUPAC name '2-Methylphenol' indicates a phenol ring with:

Q4. What is the correct IUPAC name for HO-CH2-CH(OH)-CH2-OH?

Q5. Which of the following is an ether?

Frequently asked questions

What is the main focus of these NCERT Solutions for Class 12 Chemistry Chapter 11?

These solutions primarily focus on mastering the IUPAC nomenclature for alcohols, phenols, and ethers, including writing names from structures and drawing structures from names.

How do these solutions help in understanding organic chemistry?

They provide clear, step-by-step explanations for naming organic compounds, reinforcing fundamental concepts of structure and nomenclature crucial for further study in organic chemistry.

Are the IUPAC names provided in the solutions standard?

Yes, all IUPAC names provided are in accordance with the standard nomenclature rules set by the International Union of Pure and Applied Chemistry (IUPAC).

What is the importance of drawing structures from IUPAC names?

Drawing structures from IUPAC names is a key skill that demonstrates a deep understanding of the nomenclature rules and the spatial arrangement of atoms in a molecule.

Can these solutions be used for quick revision before exams?

Absolutely. They offer concise answers and explanations that are ideal for a quick review of nomenclature rules and common compound structures.

What are the key functional groups covered in this chapter's solutions?

The key functional groups covered are alcohols (-OH), phenols (OH attached to a benzene ring), and ethers (R-O-R').

Important links

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