Question

Which among the following compound will show tautomerism?

• A. 2,2- dimethyl propanal
• B. 2,2-dimethyl - 1 nitropropane
• C. 2,2-dimethyl - 1 nitropropane
• D. Benzophenone

Answer 1

The correct option is

B & C

2,2-dimethyl - 1 nitropropane

For aldehydes and ketone to exhibit ketol-enol tautomerism, it is essential that it must have at least one alpha hydrogen. For example, acetophenone and butan-2-one show keto-enol tautomerism, but benzaldehyde and benzophenone don't show keto-enol tautomerism, since they don't have any alpha hydrogens.

(A)

In the above structure, there is no alpha hydrogen, hence it will not undergo tautomerism.

In the above B and C structures due to alpha hydrogen do undergo tautomerism.