Which of the following is an normal oxide ?

Options

A. `SiO_(2)`
B. `KO_2`
C. `BaO_2`
D. `CsO_2`

Answer

To determine which of the given options is a normal oxide, we need to understand what a normal oxide is. A normal oxide is defined as an oxide in which the oxidation state of oxygen is -2, which is the most common oxidation state for oxygen.

Let's analyze each option step by step:

1. **Option 1: SiO2 (Silicon Dioxide)**
- Silicon (Si) typically has an oxidation state of +4 in SiO2.
- Oxygen (O) has an oxidation state of -2.
- The overall oxidation state of the compound can be calculated as follows:
- For Si: +4
- For 2 O: 2 × (-2) = -4
- Total: +4 + (-4) = 0 (neutral compound)
- Since the oxidation state of oxygen is -2, SiO2 is a normal oxide.
- **Conclusion**: This option is correct.

2. **Option 2: KO2 (Potassium Superoxide)**
- Potassium (K) typically has an oxidation state of +1.
- The superoxide ion (O2^-) has a combined oxidation state of -1, which means each oxygen in O2 has an oxidation state of -1/2.
- Therefore, the oxidation state of oxygen here is not -2.
- **Conclusion**: This option is incorrect.

3. **Option 3: BaO2 (Barium Peroxide)**
- Barium (Ba) typically has an oxidation state of +2.
- The peroxide ion (O2^2-) has a combined oxidation state of -2, which means each oxygen in O2 has an oxidation state of -1.
- Therefore, the oxidation state of oxygen here is not -2.
- **Conclusion**: This option is incorrect.

4. **Option 4: CSO2 (Cesium Superoxide)**
- Cesium (Cs) typically has an oxidation state of +1.
- Similar to KO2, the superoxide ion (O2^-) has a combined oxidation state of -1, which means each oxygen in O2 has an oxidation state of -1/2.
- Therefore, the oxidation state of oxygen here is not -2.
- **Conclusion**: This option is incorrect.

After analyzing all the options, we find that the only normal oxide among the given choices is **SiO2**.

### Final Answer:
The normal oxide is **SiO2**.