Chapter 6: Haloalkanes and Haloarenes (CBSE Class 12)

Introduction

• Haloalkanes: These are the compounds obtained from alkanes by replacing one or more hydrogen atoms with a corresponding number of halogen atoms (-F, -Cl, -Br, -I).
• Haloarenes: The hydrogen atom of the benzene nucleus is substituted by a halogen and has the general formula, C₆H₅X.
• Haloalkanes contain halogen atom(s) attached to sp3 hybridized carbon atom of an alkyl group whereas haloarenes contain halogen atom(s) attached to sp2 hybridized carbon atom of a aryl group.
• Many halogen-containing organic compounds occur in nature and some of these are clinically useful.

Classification

Nomenclature

Nature of C-X Bond

Methods of Preparation of Haloalkanes

Preparation of Haloarenes

Physical Properties

Chemical Properties / Reactions

Polyhalogen Compounds

• Polyhalogen compounds are carbon compounds containing more than one halogen atom, e.g., CHCl₃, CCl₄.

Dichloromethane (Methylene Chloride), CH₂Cl₂

Trichloromethane (Chloroform), CHCl₃

Triiodomethane (Iodoform), CHI₃

Tetrachloromethane (Carbon Tetrachloride), CCl₄

Freons

p, p’-Dichlorodiphenyl Trichloroethane, DDT