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NCERT Solutions Class 11 Chemistry Chapter 9 Hydrocarbon - PDF Download

JEE Mains & Advanced

NCERT Solutions Class 11 Chemistry - Chapter 9 deals with Hydrocarbon. It's super simple to understand how hydrogen and carbon interact with each other from eSaral’s NCERT solutions. Explaining the different types of hydrocarbon will help you dive deeper into the world of organic chemistry. eSaral's expert teachers make it easy to understand hydrocarbons by providing solutions to the questions given in the exercise. All you have to do is download the free NCERT solutions free pdf by eSaral and you'll be learning the chemistry of hydrocarbons in no time.

Once you have studied the unit Hydrocarbon, you will be able to:

  • Name hydrocarbons using the IUPAC system

  • Identify and write the structures of isomers

  • Identify alkanes, alkene, alkynes, and aromatic hydrocarbons

  • Learn about the different ways of preparing hydrocarbons

  • Differentiate alkanes from alkene, alkene from alkynes, and aromatic from hydrocarbon based on physical and chemical properties

  • Distinguish between ethane conformations

  • Understand the role of hydrocarbon as a source of energy and for industrial applications

  • Understand the formation of the addition products of unsymmetrical alkynes and alkynes based on electronic mechanics

  • Understand the structure of benzene

  • Understand the aromaticity of benzene

  • Understand the electrophilic and electrotoxic effects of benzene reactions

  • Understand the direct influence of substituents in the monosubstituted benzene ring

  • Understand carcinogenicity and toxicity

NCERT Solutions for Class 11 Chemistry Chapter 9 Sections

Section Name

Topic Name












Aromatic Hydrocarbon


Carcinogenicity and Toxicity

9.1 Classification: Hydrocarbons can be divided into three distinct categories, depending on the type of carbon-carbon bond that is present which are saturated, unsaturated and aromatic hydrocarbons

9.2 Alkanes: Alkanes are made up of carbon and hydrogen molecules that are arranged in either straight or branched chains. They're an aliphatic type of hydrocarbon.

Following subtopics are discussed in the section 9.2:

       9.2.1 Nomenclature and Isomerism

       9.2.2 Preparation 

       9.2.3 Properties

       9.2.4 Conformations

9.3 Alkenes: Alkenes are unsaturated hydrocarbons with at least one carbon carbon double bond in their molecular structure.

Following subtopics are discussed in the section 9.3:

       9.3.1 Structure of double bond

       9.3.2 Nomenclature

       9.3.3 Isomerism

       9.3.4 Preparation

9.4 Alkynes: Alkynes are unsaturated hydrocarbons with at least one triple bond between two carbon atoms.

Following subtopics are discussed in the section 9.4:

       9.4.1 Nomenclature and isomerism

       9.4.2 Structure of triple bond

       9.4.3 Preparation

       9.4.4 Properties

9.5 Aromatic Hydrocarbon: Aromatic Hydrocarbons are hydrocarbons that have a special ring structure called a benzene ring or aromatic ring. They have special properties and can react with other hydrocarbons because of their ring system and the conjugation of pi (π) bonds.

Following subtopics are discussed in the section 9.5:

       9.5.1 Nomenclature and isomerism

       9.5.2 Structure of benzene

       9.5.3 Aromaticity

       9.5.4 Preparation of benzene

       9.5.5 Properties

9.6 Carcinogenicity and toxicity: Benzene and polynuclear hydrocarbons, which are made up of more than just two benzene rings, when mixed together are toxic and thought to have cancer-causing property. They get into the body and go through a bunch of different things, and eventually they mess with your DNA and end up causing cancer.

Key Points of Class 11 Chemistry Chapter 9 Hydrocarbon  

  • Carbon and hydrogen are the only compounds that make up hydrocarbons. The main sources of hydrocarbons are coal and petroleum. Petrochemical products are the primary raw materials for the production of a wide range of commercially important products. 

  • The main energy sources for domestic consumption and the automotive industry are derived from petroleum. LPG or CNG is a compressed natural gas. The hydrocarbons are divided into open chain saturated and unsaturated, cyclic and aromatic, depending on their structure.

  • When it comes to alkanes, there are a few key reactions that need to be done: they need to be free radical substituted, burned, oxidized, and aromatized. Alkanes and alkynes need to go through addition reactions which are mostly electrophilic ones. And even though aromatic hydrocarbons don't need unsaturation, they need to go through electrophilic addition reactions too, but only under special circumstances.

  • Alkanes undergo conformation isomerism because of free rotation along C-C sigma bonds. Staggered conformation is more stable out of staggered and out of the eclipsed conformation of ethane because hydrogen atoms are furthest apart from each other. Alkenes undergo geometrical isomerism (called cis-trans) because of restricted rotation around carbon-carbon double bonds.

  • Benzene and benzenoid compounds exhibit aromatic properties. The aromatic properties of these compounds are attributed to their specific electronic structure, which is governed by the Hükkel (4 n + 2)π electron principle. The presence or absence of substituted groups or groups attached to a benzene ring serves to activate or deactivate the ring towards further electrophilic substituents, as well as to direct the incoming group's orientation. Some of the polymorphic hydrocarbons containing a fused benzen ring system exhibit carcinogenic properties.

Benefits of Downloading the PDF of NCERT Solutions Class 11 Chemistry Chapter 9 Hydrocarbons

Downloading PDFs of NCERT solutions for Class 11 Chemistry chapter 9 “Hydrocarbons” can provide students with several advantages:

  • You can access the solutions anytime and anywhere as long as your device can read PDF files

  • You can revise or study on the go as soon as you download the solutions

  • You don’t need to have an active internet connection once you download the solutions, which is ideal for situations where you may not have a constant internet connection

  • If you prefer studying from printed materials, you can print out the solutions easily.

  • If you want to save time and money, PDFs are the way to go! They're usually searchable, so you can easily find the right topics or keywords in the solutions.

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  • If you're eco-friendly, you can save paper and reduce your environmental impact by choosing digital solutions.

Frequently Asked Questions

Question 1: What are hydrocarbons?

Answer 1: Organic compounds consisting exclusively of hydrogen and carbon are referred to as hydrocarbons. Hydrocarbons are the most basic type of organic compound and are the fundamental building blocks of numerous other organic molecules.

Question 2: What are aromatic hydrocarbons? 

Answer 2: Aromatic Hydrocarbons are hydrocarbons that are structurally related to benzene rings or aromatic ring structures. These compounds possess distinct properties due to resonance stabilization of pi electrons within the ring.



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