Unit – I C – 01
Monohalogen Derivatives of Alkanes OR Alkyl Halides
- When one hydrogen atom of alkane is replaced by one halogen atom, then the compound obtained is called as monohalogen derivative of alkane. They are commonly called as alkyl halides or haloalkenes. Their general formula is CnH2n+1X,
where X is either Cl, Br or I. They are also represented by a general formula R-X, where R is an alkyl group and X is a halogen.
- e.g. CH3Cl (Methyl chloride), C2H5Br (Ethyl bromide)
Classification of Monohalogen Derivatives of Alkanes OR Alkyl Halides:
A) On the Basis of Type of Carbon Atom to Which Halogen Atom is Attached :
Depending upon type of carbon atom to which halogen is attached alkyl halides are classified into three types.
1) Primary Alkyl Halides :
- Primary carbon atom is a carbon atom which is bonded to only one other carbon or to none. Primary carbon atom is denoted by 1°. In primary alkyl halide the halogen is attached to primary (1°) carbon atom.
2) Secondary Alkyl Halides :
Secondary carbon atom is a carbon atom which is bonded to two other carbon atoms. Secondary carbon atom is denoted by 2°. In secondary alkyl halide the halogen is attached to secondary (2°) carbon atom.
3) Tertiary Alkyl Halides :
Tertiary carbon atom is a carbon atom which is bonded to three other carbon atoms. Tertiary carbon atom is denoted by 3°. In tertiary alkyl halide the halogen is attached to tertiary (3°) carbon atom.