Explain classification of monohalogen compounds on the basis of `sp^(3)(C-X)` bonds. (X = F, Cl, Br, I).

Explanation

(a) Alkyl Halides : Depending upon the nature of carbon to which the halogen is bonded, the alkyl halides are classified as `1^(@)` (primary), `2^(@)` (secondary) and `3^(@)` (tertiary compounds.
`underset("Primary "(1^(@)))(R.-overset("H")overset("|")underset("H")underset("|")("C")-X) " "underset("Secondary" (2^(@)))(R..-overset("R.")overset("|")underset("H")underset("|")("C")-X)" " underset("Tertiary "(3^(@)))(R.-overset("R.")overset("| ")underset("R...")underset("| ")("C ")-X)`
`underset("Alkane")(C_(n)H_(2n+2))overset(+X" ")underset(-H" ")rarr underset("(Homologous Series)")underset("Haloalkane")(C_(n)H_(2n+1)X)`
`1^(@)` Alkyl Halide `rArr` Halogen is bonded to `1^(@)` carbon
`2^(@)` Alkyl Halide `rArr` Halogen is bonded to `2^(@)` carbon
`3^(@)` Alkyl Halide `rArr` Halogen is bonded to `3^(@)` carbon
(b) Benzylic Halides : These are the compounds in which the halogen atom is bonded to an `sp^(3)` hybridized carbon atom attached to an aromating ring.

(c ) Allyic Halides : These are the compounds in which the halogen atom is bonded to an `sp^(3)` - hybridised carbon atom adjacent to carbon - carbon double bond `(gt C = C lt)` i.e., allylic carbon.