How many structural isomers are possible with the molecular formula ${{C}_{6}}{{H}_{14}}$?

Hint: Before listing out the number of possible structural isomers of ${{C}_{6}}{{H}_{14}}$, it is important to understand the concept of structural isomerism and all possible types of structural isomers.

Complete answer:
-The isomers that differ only in the atomic arrangement and have no difference in the molecular formula are structural isomers and this phenomenon is termed structural isomerism.
-There are three types of structural isomerism and they are functional group isomerism, position isomerism and chain isomerism. When there is a difference in the atomic arrangement of the carbon to carbon chain of the molecule, then it falls in the category of chain isomerism. And when there is a difference in the position occupied by the substituent groups of atoms or an atom (the functional group) with respect to the main chain then it is termed as positional isomerism. With the same chemical formula, when there is a presence of an odd form of functional groups then it falls under functional group isomerism.
-Hexane being an aliphatic saturated hydrocarbon has $5$ possible structural isomers and they are hexane, $2$-methylpentane, $3$-methylpentane, $2,2-$dimethylbutane, $2,3-$ dimethylbutane. The above compounds just differ in terms of structure but the molecular formula of the compounds are the same.

Note:
As per IUPAC, structural isomerism is also termed constitutional isomerism, that is the compounds just differ in the order of bonding with the same molecular formula and this is completely opposite to stereoisomerism.