Why can the formula #C_5H_12# support isomerism?

1 Answer
Feb 13, 2018

Because there are branched chain molecules of the same molecular formula.

Explanation:

Pentane has #5# carbon atoms in a chain. It is #"C"_5"H"_12#. This molecular formula is also shared by a butane molecule with a methyl side chain, which can be on either #"C"# atom number #2# or #3# in the chain i.e. 2-methylbutane or 3-methylbutane.

You can also have a propane molecule with two methyl side chains both on #"C"# atom number #2# in the chain i.e. 2,2-dimethylpropane.