Lecture Notes: Haloalkanes and Haloarenes

Introduction

*** Shivling Stars, today we are starting a one-shot video lecture on the chapter 'Haloalkanes and Haloarenes.'**

• All students of the Winner Batch, keep up your hard work.
• Important statement: Do not get tired, do not stop, it is still necessary to keep moving.
• In this session, we will cover the important parts of the chapter.

Topics of Discussion

1. Introduction to Haloalkanes and Haloarenes
2. Classification: Categorizing into different groups
3. Nature of C-X Bond
4. Methods of Preparation
5. Physical and Chemical Properties
6. Conversion Questions

Chapter Introduction

• Haloalkanes: - Alkanes with a halogen atom.
• Haloarenes: - Aromatic compounds with a halogen atom.
• General formula of Haloalkanes: R-X (R: Alkyl group, X: Halogen)

Classification

• Haloalkanes:
  • Based on Number: Mono-, Di-, Tri-Haloalkanes
  • Hybridization Basis: SP2, SP3
• Haloarenes: Aromatic halogens
• Based on Branching and Stability:
  • Mono-, Di-, Tri-Haloalkanes
  • Allylic halides, Benzylic halides

Nature of C-X Bond

• Bond Length: Increases going down the group.
• Bond Dissociation Energy: Increases going up the group.
• Dipole Moment: Affected by electronegativity.

Methods of Preparation

• From Hydrocarbons:
  • Free Radical Substitution: Alkanes, Chlorination
  • Haloalkanes: Alkanes and HCl
• From Alcohols:
  • Reaction with HX: Formation of water and halogen
  • Reaction with PCl5 and PCl3:
  • Thionyl Chloride (SOCl2): Poses Brønsted reaction

Physical Properties

• Color and Smell: Colorless in unwanted conditions, colored when halogen is present
• State: Fewer alkanes are gases, higher alkanes are liquids, very high are solids
• Melting and Boiling Points: Depend on various factors
  • Boiling Point: Proportional to molecular mass
  • Melting Point: Depends on symmetry

Chemical Properties

• Nucleophilic Substitution Reactions:
  • Types: Sn1, Sn2
  • Sn2: Bimolecular, single-step reaction
  • Sn1: Unimolecular, two-step reaction
• Elimination Reactions:
  • Proceeding via Alpha and Beta Reactions

Conversion Questions

• Example: Aniline to Bromobenzene

Final Remarks

• Hard work and dedication are essential.
• Revision and Practice: Contribute more to your studies and make proper use of your time.