Write structural formula for all the isomeric alcohols having the molecular formula `C_(4)H_(10)O`.

Explanation

Some compounds can rotate the plane polarised light, when it is passed through their solution. Such compounds are called optically active compounds. The structures of the isomers of alcohols with molecular formula `C_(4)H_(10)O` are as follows

The asymmetry of the molecule is responsible for the optical activity in a molecule. If all the four substituents attached to the carbon are different then the carbon is called asymmetric of chrial carbon and such a molecule is called asymmetric molecule.
In the above explained structure, it is only butan-2-ol which contains a chrial carbon and hence it is optically active.