Which of the following is not a process of preparation of hydrogen peroxide ?

Options

A. Auto - oxidation of 2 - ethylanthraquinol.
B. By passing oxygen through boiling water.
C. By oxidation of isopropyl alcohol.
D. By reaction of barium peroxide with dil. `H_(2)SO_(4)`.

Answer

To determine which of the following is not a process of preparation of hydrogen peroxide, we will analyze each option step by step.

### Step 1: Analyze the first option - Auto oxidation of 2-ethyl anthraquinone
- The reaction involves 2-ethyl anthraquinone being oxidized in the presence of oxygen (O2) and a catalyst (H2PD).
- The reaction can be represented as:
\[ \text{2-ethyl anthraquinone} + O_2 \xrightarrow{\text{H2PD}} H_2O_2 + \text{oxidized product} \]
- This process does produce hydrogen peroxide (H2O2).

### Step 2: Analyze the second option - Passing oxygen through boiling water
- This reaction involves simply passing oxygen gas through boiling water.
- This process does not lead to the formation of hydrogen peroxide.
- Therefore, this option does not prepare hydrogen peroxide.

### Step 3: Analyze the third option - Oxidation of isopropyl alcohol
- Isopropyl alcohol (CH3CHOHCH3) can be oxidized to form acetone and hydrogen peroxide.
- The reaction can be represented as:
\[ \text{CH}_3\text{CHOHCH}_3 \xrightarrow{\text{oxidation}} \text{CH}_3\text{COCH}_3 + H_2O_2 \]
- This process does produce hydrogen peroxide.

### Step 4: Analyze the fourth option - Reaction of barium peroxide with dilute H2SO4
- The reaction involves barium peroxide reacting with dilute sulfuric acid.
- The reaction can be represented as:
\[ \text{BaO}_2 \cdot 8\text{H}_2\text{O} + \text{H}_2\text{SO}_4 \rightarrow \text{BaSO}_4 + H_2O_2 + 8\text{H}_2\text{O} \]
- This process also produces hydrogen peroxide.

### Conclusion
After analyzing all the options, we find that:
- Option A (auto oxidation of 2-ethyl anthraquinone) produces H2O2.
- Option B (passing oxygen through boiling water) does not produce H2O2.
- Option C (oxidation of isopropyl alcohol) produces H2O2.
- Option D (reaction of barium peroxide with dilute H2SO4) produces H2O2.

Thus, the correct answer is **Option B**, as it is not a process of preparation of hydrogen peroxide.