See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Order of Increasing Basicity Analysis **Step 1: Identify basicity factors** Basicity depends on the availability of the lone pair on nitrogen. More accessible lone pairs → stronger bases. **Step 2: Analyze each compound** - **Pyrrole**: N's lone pair is delocalized into the aromatic π-system (part of 6π aromaticity). Lone pair is unavailable. **Weakest base** - **Pyridine**: N has a lone pair in an sp² orbital outside the π-system, but it's still aromatic. Moderate availability. - **$Me_3N$ and $Et_3N$**: Aliphatic amines with sp³ lone pairs on nitrogen. No aromaticity constraints. Lone pair is most available. **Strong bases** **Step 3: Compare $Me_3N$ vs $Et_3N$** Both are aliphatic tertiary amines. $Et_3N$ is slightly less basic than $Me_3N$ due to greater steric hindrance from larger ethyl groups, which hinders approach of protons. **Step 4: Final order** $$\text{pyrrole} < \text{pyridine} < Me_3N < Et_3N$$ **Answer: (A)** is correct because basicity increases as the lone pair becomes more accessible and less involved in aromatic stabilization.