See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Solution: Identifying Tautomers **What are tautomers?** Tautomers are isomers that differ by migration of a hydrogen atom and a double bond between adjacent atoms. They interconvert easily and have the same molecular formula. --- ## Analysis of Option (A): **Structure 1:** Cyclohexene with $-CHCl_2$ and $-OH$ groups (enol form) **Structure 2:** Cyclohexanone with $-CHCl_2$ group (keto form) These structures can interconvert via **keto-enol tautomerism**: - The enol form (Structure 1) can lose a proton from the $-OH$ and shift the double bond - This produces the keto form (Structure 2) - Both have the **same molecular formula** $C_7H_{11}O_2Cl_2$ $$\text{Enol form} \rightleftharpoons \text{Keto form}$$ This is a classic example of tautomerization. --- ## Why others are incorrect: **(B)** Different molecular formulas — not isomers **(C)** Both are stable aromatic compounds; no hydrogen/double bond migration possible **(D)** Same molecular formula but differ in connectivity of the carbon skeleton, not by H/double bond shift — these are **structural isomers**, not tautomers **Answer: (A)** ✓