A black compound 'X' when treated with `O_(3)` turned white. The compound 'X' is

Options

A. `ZnS`
B. `PbS`
C. `CuS`
D. `Ag_(2)S`

Answer

To solve the problem, we need to identify the black compound 'X' that turns white when treated with ozone (O₃). We will analyze the options provided and determine which one fits the description.

### Step-by-Step Solution:

1. **Identify the Options**: The options given are:
- Zinc sulfide (ZnS)
- Lead sulfide (PbS)
- Copper sulfide (CuS)
- Silver sulfide (Ag₂S)

2. **Color of the Compounds**: We need to determine the color of each compound:
- **Zinc sulfide (ZnS)**: Typically white or colorless.
- **Lead sulfide (PbS)**: Known to be black in color.
- **Copper sulfide (CuS)**: Usually black.
- **Silver sulfide (Ag₂S)**: Also black.

3. **Determine Which Compound is Black**: From the analysis, we see that:
- Lead sulfide (PbS) is black and is the only compound that is specifically known to be black among the options.

4. **Reaction with Ozone**: We need to consider what happens when each of these compounds reacts with ozone (O₃):
- **Lead sulfide (PbS)** reacts with ozone to form lead sulfate (PbSO₄), which is white, along with oxygen gas (O₂).
- The reaction can be represented as:
\[ \text{PbS} + 4 \text{O}_3 \rightarrow \text{PbSO}_4 + 4 \text{O}_2 \]

5. **Conclusion**: Since lead sulfide (PbS) is black and turns white upon reaction with ozone, the compound 'X' is identified as lead sulfide (PbS).

### Final Answer:
The compound 'X' is **Lead Sulfide (PbS)**.

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