Which of the following can be oxidized by `SO_(2)`?

Options

A. `K_(2)Cr_(2)O_(7)`
B. `Mg`
C. `H_(2)O`
D. All of these.

Answer

To determine which of the given substances can be oxidized by sulfur dioxide (SO₂), we need to analyze each option provided. The options are potassium, chromate, magnesium, and water.

### Step-by-Step Solution:

1. **Understanding Oxidation**:
- Oxidation is a chemical reaction that involves the loss of electrons or an increase in oxidation state. In this case, we are looking for a substance that can be oxidized by SO₂.

2. **Analyzing Each Option**:
- **Potassium (K)**: Potassium is a highly reactive alkali metal. It does not get oxidized by SO₂ as it is already in a low oxidation state and will react with oxygen or other agents more readily.
- **Chromate (CrO₄²⁻)**: Chromate ions are already in a higher oxidation state. SO₂ is a reducing agent and typically does not oxidize chromate.
- **Magnesium (Mg)**: Magnesium can be oxidized by SO₂. The reaction can be represented as:
\[ 2 \text{Mg} + \text{SO}_2 \rightarrow 2 \text{MgO} + \text{S} \]
In this reaction, magnesium is oxidized to magnesium oxide (MgO), and sulfur from SO₂ is reduced.
- **Water (H₂O)**: Water is generally stable and does not get oxidized by SO₂ under normal conditions.

3. **Conclusion**:
- Based on the analysis, the only substance that can be oxidized by sulfur dioxide is **Magnesium (Mg)**.

### Final Answer:
The correct option is **Magnesium (Mg)**.