Which of the following correctly represents the stability of reactive intermediate?

Answer

To determine the stability of reactive intermediates, we need to analyze the given compounds based on their electronic effects and resonance stabilization. Let's break down the analysis step by step.

### Step 1: Analyze the First Compound (CH3CH2+ vs. CH3O+)
- **Structure**: We have two cations: CH3CH2+ (ethyl cation) and CH3O+ (methoxy cation).
- **Electronic Effects**:
- CH3 (methyl group) is an electron-donating group (EDG) due to hyperconjugation.
- OCH3 (methoxy group) has a lone pair that can participate in resonance, making it an electron-withdrawing group (EWG) through resonance (due to the +M effect).
- **Stability Comparison**: The resonance stabilization in CH3O+ makes it more stable than CH3CH2+ because resonance (or +M effect) is stronger than hyperconjugation and inductive effects.

**Conclusion for Step 1**: CH3O+ is more stable than CH3CH2+.

### Step 2: Analyze the Second Compound (Resonance in Cations)
- **Structure**: Consider two cations where one has a double bond adjacent to the positively charged carbon.
- **Resonance**: The cation with the double bond can delocalize the positive charge through resonance, which stabilizes the cation.
- **Stability Comparison**: The cation that can undergo resonance is more stable than one that cannot.

**Conclusion for Step 2**: The cation with resonance is more stable.

### Step 3: Analyze the Third Compound (Benzyl Cation vs. Other Cation)
- **Structure**: One cation has a benzyl group (C6H5CH2+) and the other has a substituent like NO2 or CH3.
- **Electronic Effects**:
- The benzyl cation is stabilized by resonance due to the aromatic ring.
- CH3 is an EDG, while NO2 is an EWG.
- **Stability Comparison**: The benzyl cation is more stable than the cation with NO2 because the resonance from the benzyl group outweighs the electron-withdrawing effect of NO2.

**Conclusion for Step 3**: The benzyl cation is more stable than the cation with NO2.

### Final Conclusion
All three comparisons show that the stability of reactive intermediates can be influenced by resonance and the nature of substituents (electron-donating vs. electron-withdrawing). Therefore, the options provided in the question are correct.