See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Carbocation Stability Analysis **Key Factors:** 1. **Alkyl substitution**: More alkyl groups → greater stability (hyperconjugation & inductive effects) 2. **Resonance stabilization**: Aromatic systems and conjugation provide significant stabilization 3. **Aromatic stability**: Tropylium ion ($C_7H_7^+$) is exceptionally stable due to aromaticity (6 π-electrons in a planar ring) --- ## Evaluating Each Carbocation: | Carbocation | Type | Stability Rationale | |---|---|---| | **Tropylium** ($C_7H_7^+$) | Aromatic | 6 π-electrons → aromatic, highly resonance-stabilized ✓ **Most stable** | | **$Ph_3C^+$** | Tertiary + aromatic | 3 phenyl groups provide resonance, but less delocalized than tropylium | | **$(CH_3)_3C^+$** | Tertiary alkyl | 3 methyl groups via inductive/hyperconjugation only | | **$(CH_3)_2CH^+$** | Secondary alkyl | 2 methyl groups → least stabilized | --- ## Why Option B is Correct: $$\boxed{C_7H_7^+ > Ph_3C^+ > (CH_3)_3C^+ > (CH_3)_2CH^+}$$ The **tropylium cation is most stable** due to aromaticity (Hückel's rule: $4n+2$ electrons). The $Ph_3C^+$ ranks second as aromatic rings provide better resonance than simple alkyl groups. Tertiary > secondary alkyl carbocations follow standard stability rules. **Answer: (B)**