Question

Which of the following statements about tautomerism is/are correct?
(This question has multiple correct options)
A.It is a type of functional isomerism
B.It is shown by alcohols only
C.Isomers exists in dynamic equilibrium with each other
D.Taut isomers possess a different functional group

Answer 1

Hint: To solve this question, we need to first have a detailed discussion about tautomerism and all the characteristics of this property. Then we can try to correlate the options given to us to the discussion we are about to have.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
Isomerism can be understood as the phenomenon when two or more compounds have the same molecular formula, but they have different molecular structures. To explain this in simpler terms, we can say that two or more compounds have the same constituent atoms in equal numbers, but the arrangement of these atoms within the respective molecules are different.
Now, Tautomerism can be explained as a type of isomerism that is exhibited by different compounds which involve only the change in the positions of protons and electrons, rather than the entire molecular structure. This means that positions of the constituent atoms are unaltered but the orientations of the electrons and protons are shifting. The major condition for any compound to exhibit tautomerism is that it should have at least one alpha hydrogen atom. In tautomerism, molecules with the same molecular formula interconvert rapidly. Hence, these molecules also exhibit dynamic equilibrium with each other. Also, tautomerism can be exhibited by any functional group as long as the parent chain has at least one alpha hydrogen.
Hence, pertaining to this discussion, the correct options are:
A.It is a type of functional isomerism
B.Isomers exists in dynamic equilibrium with each other
C.Taut isomers possess a different functional group

Hence, Option A, C and D is the correct option

Note: Tautomerization does not occur by the intramolecular transfer of a proton between carbon and oxygen atoms. Each of the reactions is reversible, so the acid-catalysed conversion of the enol into the keto form occurs by the reverse of each step of the mechanism.