For the lime water test , if the observation are position for the unknown sample , then which of the following conclusion (s) is /are incorrect?

Options

A. sample has only `NO_(2)`
B. sample has only ` SO_(3)`
C. sample has only `CO_(2) and SO_(2)`
D. sample has `H_(2)S`

Explanation

### Step-by-Step Solution:

1. **Understanding the Lime Water Test**:
- Lime water is a solution of calcium hydroxide (Ca(OH)₂).
- When carbon dioxide (CO₂) or sulfur dioxide (SO₂) is bubbled through lime water, a reaction occurs.

2. **Reaction with Carbon Dioxide**:
- The reaction of CO₂ with lime water can be represented as:
\[ \text{Ca(OH)}_2 + \text{CO}_2 \rightarrow \text{CaCO}_3 \downarrow + \text{H}_2O \]
- Calcium carbonate (CaCO₃) is formed, which is a white precipitate that makes the lime water appear milky.

3. **Reaction with Sulfur Dioxide**:
- The reaction of SO₂ with lime water can be represented as:
\[ \text{Ca(OH)}_2 + \text{SO}_2 \rightarrow \text{CaS} + \text{H}_2O \]
- Calcium sulfide (CaS) is formed, which also results in a white precipitate, causing the lime water to turn milky.

4. **Observations with Excess Gas**:
- If excess CO₂ is passed through the lime water, the milkiness disappears due to the formation of calcium bicarbonate:
\[ \text{CaCO}_3 + \text{CO}_2 + \text{H}_2O \rightarrow \text{Ca(HCO}_3)_2 \]
- Similarly, excess SO₂ leads to the formation of calcium bisulfide, which is also soluble:
\[ \text{CaS} + \text{SO}_2 + \text{H}_2O \rightarrow \text{Ca(HSO}_3)_2 \]

5. **Conclusion**:
- Since both CO₂ and SO₂ can cause the lime water to turn milky, a positive observation indicates the presence of either gas.
- Therefore, any conclusion stating that the positive observation is specific to only one of these gases (CO₂ or SO₂) is incorrect.