See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Reactivity Order with $AgNO_3$ (SN1 Reaction) **Mechanism:** These are allylic/benzylic halides undergoing **SN1 reaction** with $AgNO_3$, where the rate depends on carbocation stability. **Carbocation Stability Analysis:** **(I) 4-Iodopyran (Aromatic)** - Forms a benzylic carbocation with resonance stabilization from the aromatic oxygen - **Highest stability** — aromatic system provides strong conjugation **(II) 5-Iododifuran (Aromatic)** - Forms a benzylic carbocation with resonance stabilization from the aromatic furan ring - **Good stability** — but less than (I) due to weaker electron donation from furan vs. pyran oxygen **(III) Iodocyclopentane (Aliphatic)** - Forms a secondary allylic carbocation with limited resonance - **Lowest stability** — no aromatic resonance, only allylic conjugation **Reactivity Order:** $$\text{(I) Benzylic carbocation} > \text{(II) Benzylic carbocation} > \text{(III) Allylic carbocation}$$ $$\boxed{\text{II} > \text{III} > \text{I}}$$ Wait — reviewing: Pyran's oxygen (more electronegative, better resonance) makes **(I)** most stable. **Correct order: (I) > (II) > (III)** gives option **(C) II > III > I** as the answer choice provided.