Peroxo bond `(-O-O-)` is present in

Options

A. `Na_(2)O_(2)`
B. `CrO_(5)`
C. `PbO_(2)`
D. `SrO_(2)`

Explanation

To determine which compounds contain the peroxo bond `(-O-O-)`, we will analyze each given compound step by step.

### Step 1: Understand the Peroxo Bond
The peroxo bond is characterized by a single bond between two oxygen atoms, represented as `O-O`. This bond is typically found in compounds known as peroxides.

### Step 2: Analyze Each Compound

1. **Sodium Peroxide (Na2O2)**
- Structure: Na2O2 can be represented as Na+ O− O− Na+.
- Analysis: The structure shows an `O-O` bond, indicating the presence of a peroxo group.
- Conclusion: Na2O2 contains a peroxo bond.

2. **Chromium Pentoxide (CrO5)**
- Structure: CrO5 can be represented as Cr=O, O− O−.
- Analysis: The structure includes an `O-O` bond, confirming the presence of a peroxo group.
- Conclusion: CrO5 contains a peroxo bond.

3. **Lead Dioxide (PbO2)**
- Structure: PbO2 can be represented as Pb=O, Pb=O.
- Analysis: The structure does not show an `O-O` bond; instead, it has double bonds between lead and oxygen.
- Conclusion: PbO2 does not contain a peroxo bond.

4. **Strontium Peroxide (SrO2)**
- Structure: SrO2 can be represented as Sr2+ O− O−.
- Analysis: The structure shows an `O-O` bond, indicating the presence of a peroxo group.
- Conclusion: SrO2 contains a peroxo bond.

### Step 3: Final Conclusion
Based on the analysis:
- **Compounds with Peroxo Bonds**: Na2O2, CrO5, SrO2
- **Compound without Peroxo Bond**: PbO2

### Answer: The peroxo bond `(-O-O-)` is present in Na2O2, CrO5, and SrO2.

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