Sulphurous anhydride is

Options

A. `SO_(2)`
B. `SO_(3)`
C. `HSO_(3)^(-)`
D. `SO_(3)^(2-)`

Answer

To determine what Sulphurous anhydride is, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Anhydrides**:
- An anhydride is formed when a compound loses water (dehydration). In this context, we are looking for the anhydride of sulfurous acid.

2. **Identify Sulfurous Acid**:
- The chemical formula for sulfurous acid is H₂SO₃.

3. **Dehydration of Sulfurous Acid**:
- When sulfurous acid (H₂SO₃) undergoes dehydration, it loses one molecule of water (H₂O).
- The reaction can be represented as:
\[ H₂SO₃ \rightarrow SO₂ + H₂O \]
- This indicates that upon heating, sulfurous acid yields sulfur dioxide (SO₂) and water.

4. **Conclusion**:
- Therefore, the anhydride of sulfurous acid (H₂SO₃) is sulfur dioxide (SO₂).
- Thus, we can conclude that Sulphurous anhydride is SO₂.

### Final Answer:
Sulphurous anhydride is sulfur dioxide (SO₂).

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