35 Most Important Questions with Answers on Chapter Hydrocarbons Class 11 CBSE, CHSE

 

Classification of Hydrocarbons

Aliphatic Hydrocarbons :

Alkanes - Nomenclature, isomerism, conformation (ethane only), physical properties methods of preparation 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 (Markownikoff’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.

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. Carcinogenicity and toxicity.

 

 

1. What is the general formula for alkanes?

2. Why are alkanes called paraffins?

3. Explain the 'cracking' of alkanes.

4. Define isomerism in alkanes and give an example.

5. Write the Wurtz reaction and state its limitation.

6. What is the general formula for alkenes?

7. What type of hybridisation is present in the

carbon atoms of a double bond?

8. Explain the addition of HBr to propene according

to Markovnikov's rule.

9. What is the key difference between cis and trans

isomers?

10. What is Baeyer's Reagent and how is it used?

11. Explain Saytzeff's Rule (Zaitsev's Rule).

12. What is the general formula for alkynes?

13. Why are terminal alkynes (e.g., ethyne) acidic in

nature?

14. What is the product when ethyne is passed

through a red-hot iron tube?

15. Compare the C – C bond length in ethane,

ethene, and ethyne.

16. State Hückel's Rule for aromaticity.

17. Why does benzene undergo electrophilic

substitution, not addition?

18. Explain the Friedel-Crafts alkylation of benzene

with an equation.

19. Why is the nitro group NO2 meta-directing

in electrophilic substitution?

20. Give the product of the halogenation (e.g.,

chlorination) of benzene.

21. What is the significance

22. Define Aromaticity and give one example other

than benzene.

23. Write the reaction for the complete combustion

of methane.

24. How do nitrogen and sulfur in fossil fuels lead to

acid rain?

25. What is Ozonolysis and its application?