In lab `H_(2)O_(2)` is prepared by

Options

A. Cold `H_(2)SO_(4) + BaO_(2)`
B. HCl + `BaO_(2)`
C. Conc `H_(2)SO_(4) + Na_(2)O_(2)`
D. `H_(2) + O_(2)`

Answer

To solve the question regarding the preparation of hydrogen peroxide (H₂O₂) in the laboratory, we will analyze the given options step by step.

### Step 1: Analyze Option 1
- **Option 1:** Cold H₂SO₄ + Barium Peroxide
- **Reaction:** When barium peroxide (BaO₂) reacts with cold dilute sulfuric acid (H₂SO₄), it produces barium sulfate (BaSO₄) and hydrogen peroxide (H₂O₂).
- **Equation:**
\[ BaO_2 + H_2SO_4 \rightarrow BaSO_4 + H_2O_2 \]
- **Conclusion:** This option is correct as it successfully produces hydrogen peroxide.

### Step 2: Analyze Option 2
- **Option 2:** HCl + Barium Peroxide
- **Reaction:** Barium peroxide does not react with hydrochloric acid (HCl) to produce hydrogen peroxide. It primarily reacts with sulfuric acid, phosphoric acid, or carbonic acid.
- **Conclusion:** This option is incorrect.

### Step 3: Analyze Option 3
- **Option 3:** Concentrated H₂SO₄ + Sodium Peroxide
- **Reaction:** Sodium peroxide (Na₂O₂) reacts with cold dilute sulfuric acid to produce hydrogen peroxide and sodium sulfate (Na₂SO₄). However, it does not react with concentrated sulfuric acid.
- **Equation:**
\[ Na_2O_2 + H_2SO_4 \rightarrow H_2O_2 + Na_2SO_4 \]
- **Conclusion:** This option is incorrect as concentrated sulfuric acid does not yield hydrogen peroxide.

### Step 4: Analyze Option 4
- **Option 4:** H₂ + O₂
- **Reaction:** The reaction between hydrogen (H₂) and oxygen (O₂) produces water (H₂O) and not hydrogen peroxide.
- **Equation:**
\[ 2H_2 + O_2 \rightarrow 2H_2O \]
- **Conclusion:** This option is incorrect as it does not produce hydrogen peroxide.

### Final Conclusion
After analyzing all the options, the correct method for preparing hydrogen peroxide in the laboratory is:
- **Correct Option:** Cold H₂SO₄ + Barium Peroxide (Option 1).

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