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Home / Ncert Solutions for Class 11 Chemistry Chapter 13

Ncert Solutions for Class 11 Chemistry Chapter 13

NCERT Solutions for Class 11 Chemistry Chapter 13 Hydrocarbons - Hydrocarbons are the compounds having hydrogen and carbon only as their substituent elements. Hydrocarbons are mainly formed by petroleum and fuel, which are important sources of energy. This chapter talks about the classification of hydrocarbons, their properties, reactions, and uses. There are 25 questions in this chapter. The NCERT Solutions for Class 11 Chemistry Chapter 13 Hydrocarbons are prepared and designed by our subject experts. This chapter is very important from the perspective of clearing basic reactions of organic chemistry since all the elementary reactions which will be used in subsequent chapters are discussed in this chapter. You can also refer to NCERT Solutions for Class 11 Chemistry Chapter 13 Hydrocarbons for clearing your further doubts. These NCERT Solutions for Class 11 Chemistry Chapter 13 Hydrocarbons are prepared in a very comprehensive manner. Here, you will get NCERT solutions from class 6 to 12 for science and maths. It will help students in the preparation of CBSE final examination of class 11 as well as in various other competitive exams like NEET, JEE, etc. By referring to the NCERT solutions for class 11 , students can understand all the important concepts and practice questions well enough before their examination

NCERT Class 11 Chemistry syllabus of Chapter 13 Hydrocarbons discusses aliphatic hydrocarbons-alkanes, alkenes and alkynes, their IUPAC nomenclature, chemical reactions, and physical properties. After completing this chapter along with NCERT solutions for Class 11 Chemistry Chapter 13 Hydrocarbons students will be able to distinguish between alkanes, alkenes, alkynes, and aromatic compounds on the basis of chemical and physical properties, learn about the various preparation methods for hydrocarbons and also appreciate the role of hydrocarbons in industrial applications and as sources of energy.

NCERT Solutions for Class 11 Chemistry Chapter 13 Hydrocarbons- Important Points

1. Hydrocarbons are the compounds of hydrogen(H) and carbon(C) only.

2. Hydrocarbons compounds are classified as -

  • Open chain saturated compounds (alkanes)
  • Open chain unsaturated compounds (alkenes and alkynes)
  • Cyclic compounds (alicyclic)
  • Aromatic compounds

3. The important reactions are combustion, oxidation, free radical substitution, and aromatization.

4. Alkynes and alkenes hydrocarbons undergo addition reactions, which are generally electrophilic additions.

5. Aromatic hydrocarbons undergo mainly electrophilic substitution.

6. Alkanes show conformational isomerism due to the free rotation along with Carbon-Carbon sigma bonds. And due to restricted rotation around the C=C double bond, alkenes exhibit geometrical( cis-trans ) isomerism.

NCERT Class 11 Chemistry Chapter 13 Hydrocarbons- Topics

13.1 Classification

13.2 Alkanes

13.3 Alkenes

13.4 Alkynes

13.5 Aromatic Hydrocarbon

13.6 Carcinogenicity and Toxicity

NCERT Solutions for Class 11 Chemistry Chapter 13 Hydrocarbons- Exercise Questions

Q 13.1 How do you account for the formation of ethane during chlorination of methane ?

Answer:

Chlorination of methane is by free radical mechanism and it takes place in three steps-
(i) Initiation-
First, homolytic cleavage of the Cl-Cl bond as

(ii) Propagation-
Chlorine-free radicals attack methane molecule and generate methyl-free radical as

This methyl radical reacts with other molecules of chlorine ( Cl-Cl ) and form methyl chloride and liberate chlorine-free radicals.

Then chlorine free radical reacts with methyl chloride and this way propagation occurs.


(iii) Termination-
Ethane will be produced as a final product in this step. When two methyl free radicals react with each other ethane will be formed.

Q 13.7 Propanal and pentan-3-one are the ozonolysis products of an alkene? What is the structural formula of the alkene?

Answer:

In the process of ozonolysis, an ozonide, cyclic ring structure intermediate is formed, which undergoes cleavage to give the product. The parent compound produces pentan-3-one and propanal. So, the possible structure should be-

Here in this above structure, right side Pent-3-one and the left-hand side propanal structure.

Thus, by removing the ozone from ozonide we can get the parent alkene structure.
Therefore the structure of the parent alkene is

(3-ethyl-3-hexene)

Q 13.11 What are the necessary conditions for any system to be aromatic?

Answer:

The necessary conditions for any system to be aromatic are -

  1. The cyclic compound should be a planner
  2. The complete(continuous) delocalisation of \pi -electrons in the ring
  3. Follow the Huckel rule- it states that, the ring has (4n+2) \pi -electrons, where n =integer(n = 0, 1, 2, 3....)

Q 13.13(i) How will you convert benzene into

p-nitrobromobenzene

Answer:

Bromination of a benzene ring in the presence of anhydrous FeCl_{3} and Br_{2} gives bromobenzene and after that treating bromobenzene with conc. nitric acid in the presence of sulphuric acid followed by fractional distillation gives p-nitrobenzene.

Q 13.14 (ii) How will you convert benzene into

m- nitrochlorobenzene

Answer:

Benzene on treatment with conc. nitric acid and sulphuric acid gives nitrobenzene which on further treatment with chlorine in the presence of anhydrous aluminium chloride ( AlCl_{3} ) gives m-nitrochlorobenzene.

Q 13.13(iii) How will you convert benzene into

p - nitrotoluene

Answer:

Alkylation of benzene gives in the presence of anhydrous aluminium chloride give methylbenzene and HCl . When methylbenzene reacts with conc. nitric acid and sulphuric acid gives a mixture of para and ortho product of nitrotoluene, which on distillation gives p -nitrotoluene.

Q 13.15 What effect does branching of an alkane chain has on its boiling point?

Answer:

On an increase in the branching of the alkane, the boiling point of the alkane is decreased. Alkane experience inter-molecular van der Waals forces. The strong is the force, strong will be the boiling point. When we increase the branching, the surface area of the molecule decreases, as a result, of the van der Waals force also decreases.

Q 13.23 Out of benzene, m–dinitrobenzene and toluene which will undergo nitration most easily and why?

Answer:

Nitration is occurred by an electrophilic substitution reaction, in which an electron rich species is attacked by an electron deficient molecule known as an electrophile. In nitration NO_{2}^+ is used as an electrophile. Here methyl group is electron donating group and the nitro group is electron withdrawing group. So, benzene ring attached with the -CH_{3} group has high electron density and the ring which is attached with the nitro group has least electron density. Hence toluene undergoes nitration most easily.

NCERT Solutions for Class 11 Chemistry

NCERT Class 11 Solutions

  • NCERT solutions for Class 11 Biology
  • NCERT solutions for Class 11 Maths
  • NCERT solutions for Class 11 Chemistry
  • NCERT solutions for Class 11 Physics

Benefits of NCERT Solutions for Class 11 Chemistry Chapter 13 Hydrocarbons

  • Homework will be easy now, all you need to do is check the detailed NCERT Solutions for Class 11 Chemistry Chapter 13 Hydrocarbons and you are good to go.
  • The revision will be quite easier for you now, which will eventually help in remembering the concepts for a longer duration and get you very good marks in your examination.
  • The solutions which are provided here will also help you in building your concepts as well as a strong base in the subject.
  • The solutions are provided here are as per the CBSE guidelines, hence these solutions are sought after by large number of students to score high marks in their CBSE examinations.

If you have any doubt or question that is not available here or in any of the chapters, contact us. You will get all the answers that will help you score well in your exams.

Solutions

Frequently Asked Question (FAQs) - NCERT Solutions for Class 11 Chemistry Chapter 13 Hydrocarbons

Question: What are the important topics NCERT class 11 chemistry chapter 13 ?

Answer:

- Classification of Hydrocarbons

- Aliphatic Hydrocarbons

- Aromatic Hydrocarbons: Introduction, IUPAC nomenclature,

- Benzene: resonance, aromaticity, chemical properties: mechanism of electrophilic substitution. Nitration, sulphonation, halogenation, Friedel Craft's alkylation and acylation, directive influence of functional group in monosubstituted benzene.

- Alkanes - Nomenclature, isomerism, conformation (ethane only), physical properties, chemical reactions including free radical mechanism of halogenation, combustion and pyrolysis.

- Alkenes - Nomenclature, structure of double bond (ethene), geometrical isomerism, physical properties, methods of preparation, chemical reactions: addition of hydrogen, halogen, water, hydrogen halides (Markownikov's addition and peroxide effect), ozonolysis, oxidation, mechanism of electrophilic addition.

- Alkynes - Nomenclature, structure of triple bond (ethyne), physical properties, methods of preparation, chemical reactions: acidic character of alkynes, addition reaction of - hydrogen, halogens, hydrogen halides and water.

- Carcinogenicity and toxicity.

Question: What is the weightage of NCERT class 11 Chemistry chapter 13 in NEET ?

Answer:

This chapter holds the weightage of 3%

Question: Where can I find complete solutions of NCERT class 11 Chemistry?

Question: What is the official website of NCERT ?

Question: What is the weightage of NCERT class 11 Chemistry chapter 13 in CBSE board exam ?

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NCERT Solutions for Class 11 Chemistry Chapter 13 Hydrocarbons

Ncert Solutions for Class 11 Chemistry Chapter 13

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