`H_(2)O_(2)` cannot be synthesized by

Options

A. Addition of ice cold `H_(2)SO_(4)` on `BaO_(2)`
B. Addition of ice cold `H_(2)SO_4` on `PbO_(2)`
C. Aerial oxidation of 2-ethyl anthraquinol
D. Electrolysis of `(NH_4)_2SO_(4)` at a high current density

Answer

To determine which method cannot synthesize hydrogen peroxide (H₂O₂), let's analyze the options provided in the video transcript step by step.

### Step 1: Understanding the Synthesis of H₂O₂
Hydrogen peroxide (H₂O₂) can be synthesized through various chemical reactions, particularly involving peroxy compounds or specific reactions that yield H₂O₂ as a product.

### Step 2: Analyzing Each Method
1. **Addition of ice-cold H₂SO₄ on BaO₂**:
- BaO₂ (barium peroxide) is a peroxy compound.
- When ice-cold H₂SO₄ is added to BaO₂, it reacts to produce H₂O₂ and BaSO₄ (barium sulfate), which precipitates out.
- **Conclusion**: This method can synthesize H₂O₂.

2. **Addition of ice-cold H₂SO₄ on PbO₂**:
- PbO₂ (lead dioxide) is not a peroxy compound.
- When H₂SO₄ is added to PbO₂, it produces PbSO₄ (lead sulfate) and releases oxygen gas (O₂) instead of H₂O₂.
- **Conclusion**: This method cannot synthesize H₂O₂.

3. **Areal oxidation of 2-ethyl anthraquinol**:
- This method involves the oxidation of anthraquinol in the presence of oxygen.
- The process can yield H₂O₂ as a product.
- **Conclusion**: This method can synthesize H₂O₂.

4. **Electrolysis of NH₄O₂SO₄ at high current density**:
- Electrolysis of ammonium peroxodisulfate (NH₄O₂SO₄) can lead to the formation of H₂O₂ through hydrolysis.
- **Conclusion**: This method can synthesize H₂O₂.

### Final Conclusion
Based on the analysis, the method that **cannot** synthesize H₂O₂ is:
**Addition of ice-cold H₂SO₄ on PbO₂.**

### Answer
**H₂O₂ cannot be synthesized by the addition of ice-cold H₂SO₄ on PbO₂.**

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