See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

## Solution **Understanding the Reaction:** Pyrrole ($C_4H_5N$) with a five-membered aromatic ring containing N–H is treated with a carbene (:C with two lone pairs), which is a nucleophile/electrophile. **Step 1: Identify the reactive site** The N–H in pyrrole is acidic due to the aromatic system. The carbene (:C) acts as a strong electrophile and abstracts the acidic proton: $$\text{Pyrrole} + :C \rightarrow \text{Pyrrole}^- + HC$$ **Step 2: Recognize the product structure** After H⁺ abstraction, pyrrole forms a pyrrolide anion (pyrrole with negative charge on nitrogen). The carbene then inserts or the N⁻ attacks, but the net result shown in option (A) is simply **pyridine** ($C_5H_5N$). **Step 3: Why option (A) is correct** - **(A) Pyridine**: Six-membered aromatic ring with N replacing CH. This forms when the pyrrole's N–H bond is converted to a pyridine structure. ✓ - **(B)** Pyridinium salt with Cl⁻ — would form only if carbene adds and creates a positively charged intermediate (not the primary product) - **(C)** Chlorobenzene — incorrect ring type and substituent - **(D)** Chloropyridine — introduces Cl, which doesn't come from the reaction conditions **Answer: (A) Pyridine** — the carbene reaction causes rearrangement/substitution of pyrrole to form the aromatic six-membered pyridine ring.