Chemistry - STRUCTURAL ISOMERISM Question with Solution | TestHub

(P) → (2) Ring-chain tautomerism

• Sugar structure shows open-chain ⇄ cyclic form.
• Interconversion between ring and chain form occurs.
• Hence ring-chain tautomerism.

(Q) → (1) Nitroso–oxime tautomerism

• (CH₃)₂CHNO ⇄ (CH₃)₂C=NOH
• –NO ⇄ –NOH conversion occurs.
• Hence nitroso–oxime tautomerism.

(R) → (4) Nitro–aci-nitro tautomerism

• Conversion between nitro form and aci-nitro form.
• Involves proton shift and change in bonding.
• Hence nitro–aci-nitro tautomerism.

(S) → (5) Keto–enol tautomerism

• Enol form ⇄ keto form (C=C–OH ⇄ C=O).
• Proton shift with double bond migration.
• Hence keto–enol tautomerism.