See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Basic Strength Order of Nitrogen-Containing Compounds **Identify each compound:** - (1) Piperidine: saturated 6-membered ring with $NH$ - (2) Pyridine: aromatic 6-membered ring with $N$ - (3) Morpholine: saturated 6-membered ring with $O$ and $NH$ - (4) Pyrrole: aromatic 5-membered ring with $NH$ **Key factors determining basicity:** 1. **Aromaticity effect:** Aromatic compounds (2, 4) are **weaker bases** than saturated ones (1, 3) because lone pair participation in the aromatic system reduces availability for protonation. 2. **Electron-withdrawing atoms:** Oxygen in morpholine (3) is highly electronegative, withdrawing electron density from nitrogen, making it **weaker than piperidine** (1). 3. **Ring size and saturation:** Saturated 6-membered ring (piperidine) has the most available lone pair electrons → **strongest base**. **Ranking:** $$\text{Piperidine (1)} > \text{Morpholine (3)} > \text{Pyrrole (4)} > \text{Pyridine (2)}$$ $$(1) > (3) > (4) > (2)$$ **Answer: (D)**