Write the structures of the isomers of alcohols with molecular formula C4H10O. Which of these exhibits optical activity

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 C4H10O as follows.
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The asymmetry of the molecule is responsible for the optical activity in four substituents attached to the carbon are different then the carbon is called asymmetric or chiral carbon and such a molecule is called asymmetric molecule.
In the above explained structure, it is only butan-2-ol which contains a chiral carbon and hence it is optically active.