Question

Which of the following compounds will undergo tautomerism?

• A.
• B.
• C.
• D. All of the above

Answer 1

The correct option is A

Tautomerism is a phenomenon where a single compound tends to exist in two or more structures which are interconvertible and differ in the relative position of one atomic nucleus.
Isomers exhibiting tautomerism are called tautomers.
Tautomers differ in arrangement of atoms but they exist in dynamic equilibrium with each other.

Generally, compounds with alpha hydrogens will undergo tautomerism.
Compound (c) does not have alpha hydrogen, so it does not undergo tautomerism.

In compound (b), the alpha hydrogen is attached to $s{p}^2$ hybridised carbon. Hence, tautomerism is not possible here.

Compound (a) shows tautomerism due to presence of alpha hydrogens.