Which of the following do not contain peroxide ions

Options

A. `PbO_(2)`
B. `H_(2)O_(2)`
C. `SrO_(2)`
D. `BaO_(2)`

Explanation

To determine which of the given compounds do not contain peroxide ions, we first need to understand what a peroxide ion is. The peroxide ion is represented as \( O_2^{2-} \), which means it consists of two oxygen atoms bonded together with a -2 charge.

### Step-by-Step Solution:

1. **Identify Peroxide Ion**:
- The peroxide ion is \( O_2^{2-} \). Any compound that contains this ion is classified as a peroxide.

2. **List the Compounds**:
- We need to analyze the given compounds to check if they contain the peroxide ion. Common examples of peroxides include \( H_2O_2 \) (hydrogen peroxide), \( BaO_2 \) (barium peroxide), and \( SrO_2 \) (strontium peroxide).

3. **Examine Lead(IV) Oxide \( PbO_2 \)**:
- \( PbO_2 \) is lead(IV) oxide. In this compound, lead is in the +4 oxidation state. The oxide ion present here is \( O^{2-} \), not \( O_2^{2-} \). Therefore, \( PbO_2 \) does not contain the peroxide ion.

4. **Conclusion**:
- Since \( PbO_2 \) does not contain the peroxide ion, it is the correct answer to the question.

### Final Answer:
- The compound that does not contain peroxide ions is **\( PbO_2 \)**.