Branching starts from hydrocarbons with 4 carbon atoms.
Example-
1. Butane - C H : [Two isomers]
4 10
Common Name- n-butane Common Name- Iso - butane
IUPAC Name- Butane IUPAC Name- 2-methyl, propane.
2. Pentane – C H : [Three isomers]
5 12
Common Names of Pentane-
3