Which of the following is a paramagnetic compound ?

Options

A. `KO_2`
B. `SiO_2`
C. `TiO_2`
D. `BaO_2`

Answer

To determine which of the given compounds is paramagnetic, we need to analyze the electronic configurations of each compound and check for unpaired electrons. A compound is considered paramagnetic if it has one or more unpaired electrons.

### Step-by-Step Solution:

1. **Identify the Compounds:**
The compounds given are:
- KO2 (Potassium superoxide)
- SiO2 (Silicon dioxide)
- TiO2 (Titanium dioxide)
- BaO2 (Barium peroxide)

2. **Analyze KO2:**
- KO2 is a superoxide. In superoxides, the oxygen has an oxidation state of -1/2, which means it has one unpaired electron.
- Therefore, KO2 has unpaired electrons and is **paramagnetic**.

3. **Analyze SiO2:**
- Silicon (Si) has an atomic number of 14, with an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p².
- In SiO2, silicon uses its outer electrons to form bonds with oxygen, resulting in no unpaired electrons.
- Thus, SiO2 is **diamagnetic**.

4. **Analyze TiO2:**
- Titanium (Ti) has an atomic number of 22, with an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 3d² 4s².
- In TiO2, titanium also uses its outer electrons to bond with oxygen, leading to no unpaired electrons.
- Therefore, TiO2 is also **diamagnetic**.

5. **Analyze BaO2:**
- Barium (Ba) has an atomic number of 56, with an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s².
- In BaO2, barium bonds with oxygen, and there are no unpaired electrons.
- Hence, BaO2 is **diamagnetic**.

### Conclusion:
Based on the analyses, the only compound that is paramagnetic is **KO2** (Potassium superoxide).

### Final Answer:
**KO2 is the paramagnetic compound.**

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