Which one of the following is not true peroxide ?

Options

A. `PbO_2`
B. `BaO_2`
C. `Na_2 O_2`
D. `H_2 O_2`

Answer

To determine which of the given compounds is not a true peroxide, we need to analyze the oxidation states of oxygen in each compound. A true peroxide contains an O-O bond where each oxygen has an oxidation state of -1.

### Step-by-Step Solution:

1. **Identify the compounds**: The compounds given are PbO2, BaO2, Na2O2, and H2O2.

2. **Analyze PbO2**:
- Lead (Pb) has an oxidation state of +4.
- Let the oxidation state of oxygen be \( x \).
- The equation becomes: \( 2x + 4 = 0 \).
- Solving for \( x \):
\[ 2x = -4 \implies x = -2 \]
- Since the oxidation state of oxygen is -2, PbO2 does not have the O-O bond characteristic of peroxides. Thus, PbO2 is not a true peroxide.

3. **Analyze BaO2**:
- Barium (Ba) has an oxidation state of +2.
- Let the oxidation state of oxygen be \( x \).
- The equation becomes: \( 2x + 2 = 0 \).
- Solving for \( x \):
\[ 2x = -2 \implies x = -1 \]
- The oxidation state of oxygen is -1, indicating that BaO2 is a true peroxide.

4. **Analyze Na2O2**:
- Sodium (Na) has an oxidation state of +1.
- Let the oxidation state of oxygen be \( x \).
- The equation becomes: \( 2x + 2 = 0 \).
- Solving for \( x \):
\[ 2x = -2 \implies x = -1 \]
- The oxidation state of oxygen is -1, indicating that Na2O2 is also a true peroxide.

5. **Analyze H2O2**:
- Hydrogen (H) has an oxidation state of +1.
- Let the oxidation state of oxygen be \( x \).
- The equation becomes: \( 2x + 2 = 0 \).
- Solving for \( x \):
\[ 2x = -2 \implies x = -1 \]
- The oxidation state of oxygen is -1, indicating that H2O2 is a true peroxide.

### Conclusion:
The only compound that does not exhibit the characteristics of a true peroxide is **PbO2**.

### Final Answer:
**PbO2 is not a true peroxide.**

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