See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Solution: Maximum π-electron density in the ring **Key Principle:** π-electron density in an aromatic ring increases with electron-donating (activating) groups attached to the ring, due to resonance effects. **Analysis of each option:** **(A) Toluene (methylbenzene):** - $CH_3$ is directly attached to the benzene ring - Alkyl groups are electron-donating through the inductive effect - $CH_3$ donates electron density into the π-system via resonance - This increases π-electron density in the ring ✓ **(B) Benzene with $-CH_2-CH_3$ (ethylbenzene):** - The $CH_2$ group is saturated (sp³ hybridized) - Separated from the ring by a $sp^3$ carbon - Cannot participate in resonance with the π-system - Minimal electron donation to the ring **(C) Benzene with $-CH(CH_3)_2$ (isopropylbenzene):** - Similar to (B): the $CH$ is sp³ hybridized - Electron-donating power is greatly reduced - No resonance contribution **(D) Benzene with $-C(CH_3)_3$ (tert-butylbenzene):** - The quaternary carbon is sp³ hybridized - Bulky group causes steric hindrance - No resonance effect; inductive donation is weakest among all options **Conclusion:** Only in **(A)** is the electron-donating group directly conjugated with the π-system, maximizing electron density in the aromatic ring through resonance stabilization. **Answer: (A)**