Question

Keto-enol tautomerism occurs in :

• A. $A$
• B. $B$
• C. Both $A$ and $B$
• D. None of these

Answer 1

The correct option is B $B$

The carbon-oxygen distance was found to be $143$ pm in the compound $A$ and $124$ pm in compound $B$.

Thus compound $A$ has $C-O$ single bond and compound B has $C=O$ double bond.

The compound containing $C=O$ double bond shows keto-enol tautomerism.

Hence, keto-enol tautomerism occurs in $B$.