See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Why $PhN_2^+$ is More Stable than $RN_2^+$ **Step 1: Identify the structure** $PhN_2^+$ (phenyldiazonium ion) has a positive charge on the terminal nitrogen atom, directly attached to the phenyl ring ($C_6H_5-\overset{+}{N}=N$). **Step 2: Recognize delocalization pathway** The positive charge on nitrogen can delocalize into the aromatic $\pi$-electron system of the benzene ring through resonance: $$Ph-\overset{+}{N}=N \leftrightarrow Ph^{\delta+}(with\ \pi\ character) - N=N$$ The lone pair electrons from the benzene ring stabilize the positive charge by distributed it across the aromatic system. **Step 3: Compare with alkyl diazonium ($RN_2^+$)** For $RN_2^+$ where R is an alkyl group (e.g., $CH_3N_2^+$), the alkyl carbon cannot participate in resonance delocalization because: - Alkyl groups lack $\pi$-electrons - The positive charge remains localized on nitrogen - No stabilization occurs **Step 4: Conclusion** The **delocalization of positive charge into the aromatic ring** (option A) is the key reason $PhN_2^+$ is more stable. This resonance stabilization is absent in alkyl diazonium ions. **Answer: (A)** ✓