Question

Which of the following statement(s) is/are correct about tautomers:
I. They possess different electronic and atomic arrangements.
II. They possess different electronic but same atomic arrangements.
III. They have different atomic arrangements but the same electronic arrangements.
IV. They exist in equilibrium.

• A. I, IV
• B. I, III
• C. II, IV
• D. II, III

Answer 1

The correct option is A I, IV

Tautomers possess different electronic and atomic arrangements. For example, Keto and enol, both forms have different atomic arrangement and electronic arrangement around the atoms due to delocalisation of $\pi e^{-}$ and exchange of $H$ atom between $C$ and $O$ atoms.
Tautomers exist in dynamic equilibrium with each other.