Chain isomerism, also known as constitutional isomerism, is a type of isomerism that occurs when compounds have the same molecular formula but a different arrangement of atoms in the molecule. This type of isomerism occurs when a molecule has multiple ways of forming covalent bonds between its atoms, resulting in different structural arrangements.An example of chain isomerism is in the case of C4H8O, which can exist as two constitutional isomers, namely, butan-1-ol and 2-methylpropan-1-ol. Both compounds have the same molecular formula but different structural arrangements of carbon atoms, resulting in different chemical and physical properties.Another example is in the case of C6H14, which can exist as two constitutional isomers, namely, hexane and 2-methylpentane. Both compounds have the same molecular formula but different structural arrangements of carbon atoms, resulting in different chemical and physical properties.Chain isomerism is common in molecules with a higher number of carbon atoms, where there are many possible ways to arrange the atoms.