The starting material for convenient preparation of deuterated hydrogen peroxide `(D_2O_2)` in laboratory is:

Options

A. 2-ethylanthraquinol
B. `BaO_2`
C. `BaO`
D. `K_2S_2O_8`

Answer

To solve the question regarding the starting material for the convenient preparation of deuterated hydrogen peroxide (D₂O₂) in the laboratory, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Deuterated Hydrogen Peroxide**:
- Deuterated hydrogen peroxide (D₂O₂) contains deuterium (D), which is an isotope of hydrogen (H). This means that instead of regular hydrogen atoms, the molecule contains deuterium atoms.

2. **Identifying Possible Starting Materials**:
- We are given four options:
1. 2-Ethylen
2. Barium oxide (BaO)
3. Barium oxide (BaO)
4. Potassium thiosulfate (K₂H₂O₈)

3. **Analyzing the Options**:
- To prepare D₂O₂, we need a source of deuterium. The most common and convenient source of deuterium in the laboratory is deuterated water (D₂O).
- Among the given options, potassium thiosulfate (K₂H₂O₈) is known to react with D₂O to produce D₂O₂.

4. **Chemical Reaction**:
- When potassium thiosulfate (K₂H₂O₈) is treated with deuterated water (D₂O), it forms deuterated hydrogen peroxide (D₂O₂) and potassium deuterated sulfate (KdSO₄).

5. **Conclusion**:
- Therefore, the most convenient starting material for the preparation of deuterated hydrogen peroxide (D₂O₂) in the laboratory is **Potassium thiosulfate (K₂H₂O₈)**.

### Final Answer:
The starting material for convenient preparation of deuterated hydrogen peroxide (D₂O₂) in the laboratory is **K₂H₂O₈ (Potassium thiosulfate)**.

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