HS 2nd year Chemistry Unit 6: Haloalkanes and Haloar

 

🔹Topic: Introduction to Haloalkanes and Haloarenes

Q1. What are haloalkanes and haloarenes? How are they classified?
Answer:
Haloalkanes and haloarenes are organic compounds where one or more hydrogen atoms in an aliphatic or aromatic hydrocarbon are replaced by halogen atoms.

• Haloalkanes: Halogen attached to sp³ carbon of an alkyl group.

• Haloarenes: Halogen attached to sp² carbon of an aromatic ring.

They are classified as:
(i) Mono, di or poly halogen compounds depending on number of halogen atoms.
(ii) According to the type of carbon (sp³/sp²) the halogen is bonded to.

Keywords with Bengali Meaning:

• Haloalkanes – হ্যালোআলকেন

• Haloarenes – হ্যালোঅ্যারিন

• Aliphatic hydrocarbon – সোজা শৃঙ্খলযুক্ত হাইড্রোকার্বন

• Aromatic hydrocarbon – সুগন্ধযুক্ত হাইড্রোকার্বন

• Halogen – হ্যালোজেন

• sp³/sp² hybridised carbon – sp³/sp² সংকরিত কার্বন

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🔹Topic: Classification of Halogenated Compounds

Q2. What are primary, secondary, and tertiary alkyl halides?
Answer:

• Primary (1°): Halogen attached to a carbon bonded to one other carbon.

• Secondary (2°): Halogen attached to a carbon bonded to two other carbons.

• Tertiary (3°): Halogen attached to a carbon bonded to three other carbons.

Keywords with Bengali Meaning:

• Primary alkyl halide – প্রাথমিক অ্যালকাইল হ্যালাইড

• Secondary alkyl halide – মাধ্যমিক অ্যালকাইল হ্যালাইড

• Tertiary alkyl halide – তৃতীয়িক অ্যালকাইল হ্যালাইড

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🔹Topic: Nomenclature

Q3. How are haloalkanes and haloarenes named in IUPAC system?
Answer:
Haloalkanes are named as substituted alkanes using prefix of halogen (fluoro-, chloro-, bromo-, iodo-) before the name of parent alkane.
Haloarenes are named by numbering the ring such that the halogen gets the lowest number.

Example:

• CH₃CH₂Cl → Chloroethane

• C₆H₅Cl → Chlorobenzene

Keywords with Bengali Meaning:

• Nomenclature – নামকরণ

• IUPAC – আইইউপিএসি

• Substituted hydrocarbon – প্রতিস্থাপিত হাইড্রোকার্বন

🧪 Class 12 Chemistry Worksheet – Chapter 6: Haloalkanes and Haloarenes (Part 1)

📘 Topic: Introduction & Classification

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Section A: Very Short Answer Questions (1 mark each)

1. What is a haloalkane?

2. What type of carbon is bonded to halogen in haloarenes?

3. What is the hybridisation of carbon in haloalkanes?

4. What is the Bengali meaning of "halogen"?

5. Name the halogenated antibiotic effective against typhoid.

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Section B: Short Answer Questions (2–3 marks each)

6. Write any two differences between haloalkanes and haloarenes.

7. Define mono, di, and poly halogen compounds with examples.

8. Classify the following alkyl halide as primary, secondary, or tertiary:
   a. CH₃CH₂CH₂Br
   b. CH₃CH(Br)CH₃
   c. (CH₃)₃CBr

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Section C: Long Answer Questions (5 marks each)

9. Explain with examples how haloalkanes are classified on the basis of the carbon atom attached to the halogen.

10. Describe the IUPAC rules for naming haloalkanes and haloarenes with at least two examples.

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Section D: Fill in the Blanks (with Bengali keyword meanings)

11. A compound where halogen is attached to an aromatic ring is called __________. (Bengali: হ্যালোঅ্যারিন)

12. Halogen bonded to a carbon with single bonds is called __________. (Bengali: স্পি³ সংকরিত কার্বন)

13. The IUPAC name of CH₃CH₂Cl is __________. (Bengali: ক্লোরোইথেন)

14. The term "haloalkane" in Bengali is __________.

15. The type of alkyl halide where halogen is bonded to a carbon attached to three alkyl groups is called __________. (Bengali: তৃতীয়িক অ্যালকাইল হ্যালাইড)

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Section E: Match the Following

Column A	Column B
1. sp² hybridised carbon	a. Haloalkane
2. Chlorobenzene	b. Tertiary halide
3. (CH₃)₃CBr	c. IUPAC name of CH₃CH₂Cl
4. 1° alkyl halide	d. C₆H₅Cl
5. Chloroethane	e. Halogen on CH₃ group