`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 solve the question regarding the synthesis of hydrogen peroxide (H₂O₂), we will analyze each option provided and determine whether H₂O₂ can be synthesized from them.

### Step-by-Step Solution:

1. **Option A: Addition of ice-cold H₂SO₄ on BaO₂**
- When barium oxide (BaO₂) reacts with ice-cold sulfuric acid (H₂SO₄), it produces barium sulfate (BaSO₄) as a precipitate and hydrogen peroxide (H₂O₂).
- **Conclusion**: H₂O₂ can be synthesized from this reaction.

2. **Option B: Addition of ice-cold H₂SO₄ on PbO₂**
- When lead oxide (PbO₂) reacts with ice-cold sulfuric acid (H₂SO₄), it produces lead sulfate (PbSO₄) as a precipitate along with water (H₂O) and oxygen (O₂), but not hydrogen peroxide (H₂O₂).
- **Conclusion**: H₂O₂ cannot be synthesized from this reaction.

3. **Option C: Aerial oxidation of 2-ethyl anthraquinone**
- The aerial oxidation of 2-ethyl anthraquinone leads to the production of hydrogen peroxide (H₂O₂).
- **Conclusion**: H₂O₂ can be synthesized from this reaction.

4. **Option D: Electrolysis of NH₄H₂SO₄ at high current density**
- The electrolysis of ammonium sulfate (NH₄H₂SO₄) at high current density can also produce hydrogen peroxide (H₂O₂).
- **Conclusion**: H₂O₂ can be synthesized from this reaction.

### Final Answer:
Based on the analysis, the option that does not lead to the synthesis of hydrogen peroxide (H₂O₂) is **Option B: Addition of ice-cold H₂SO₄ on PbO₂**.

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