What is tautomerism?

What is tautomerism ?

The compounds which same molecular formulae of different groups which are interconvertable at room temperature are called as tautomers and the phenomenon is called as “tautomerism”.
Example:
Keto-enol isomers
Propanone :left_right_arrow: Propenol
CH3- CO -CH3 :left_right_arrow: CH3- C(OH) =CH2