The roasting of `HgS` in air produces

Options

A. `HgO`
B. `HgCl_2`
C. `HgSO_4`
D. `Hg`

Explanation

To solve the question regarding the roasting of HgS (mercury sulfide) in air, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Roasting**:
- Roasting is a metallurgical process that involves heating sulfide ores in the presence of oxygen (air) to convert them into oxides or other compounds. This process is typically used to extract metals from their ores.

2. **Identify the Ore**:
- In this case, the ore is mercury sulfide (HgS). It is a common source of mercury.

3. **Chemical Reaction**:
- When HgS is roasted in air, it undergoes a chemical reaction. The sulfur in HgS reacts with oxygen from the air to form sulfur dioxide (SO2), while mercury (Hg) is released as a metal.
- The balanced chemical equation for this reaction is:
\[ 2 \text{HgS} + 3 \text{O}_2 \rightarrow 2 \text{Hg} + 2 \text{SO}_2 \]

4. **Products of the Reaction**:
- From the reaction, we can see that the products are:
- Mercury (Hg) - which is the metal we want to extract.
- Sulfur dioxide (SO2) - a gas that is released during the process.

5. **Conclusion**:
- Therefore, the roasting of HgS in air produces mercury and sulfur dioxide.

### Final Answer:
The roasting of HgS in air produces mercury (Hg) and sulfur dioxide (SO2).

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