Main ore of lead is galena. This is mined and separated from other minerals by froth flotation. There are two methods of extracting the lead.
I. First method involves the roasting of ore followed by reduction with coke or CO.
II.Second method involves the partial roasting of ore followed by self reduction.
Which of the following statements is correct about the extraction of lead from galena?
P. Galena is a sulphide ore and therefore, it is concentrated by froth flotation process.
Q. Self reduction takes place in absence of air.
R. Complete roasting of galena gives PbO which is then reduced by coke or CO to give metallic lead
S.`FeSiO_(3)` is obtained as slag.

Options

A. P, Q, R
B. R, S
C. P, Q, R, S
D. None

Answer

To solve the question regarding the extraction of lead from galena, we will analyze each statement provided and verify their correctness based on the extraction methods mentioned.

### Step-by-Step Solution:

1. **Understanding Galena**:
- Galena is the main ore of lead, with the chemical formula PbS (lead sulfide). It is primarily concentrated using the froth flotation process, which is effective for sulfide ores.

**Hint**: Remember that froth flotation is a common method for concentrating sulfide ores.

2. **First Method of Extraction**:
- The first method involves roasting the galena (PbS) to convert it into lead(II) oxide (PbO). The reaction can be represented as:
\[ 2 \text{PbS} + 3 \text{O}_2 \rightarrow 2 \text{PbO} + 2 \text{SO}_2 \]
- After roasting, the PbO is then reduced using coke (carbon) or carbon monoxide (CO) to obtain metallic lead (Pb):
\[ \text{PbO} + \text{C} \rightarrow \text{Pb} + \text{CO} \]

**Hint**: Roasting converts sulfide to oxide, and reduction converts oxide to metal.

3. **Second Method of Extraction**:
- The second method involves partial roasting of galena, which allows for self-reduction. The reaction can be summarized as:
\[ 2 \text{PbS} + 3 \text{O}_2 \rightarrow 2 \text{PbO} + 2 \text{SO}_2 \]
\[ 2 \text{PbO} + \text{PbS} \rightarrow 3 \text{Pb} + \text{SO}_2 \]
- This process occurs in the absence of air, which is crucial for self-reduction.

**Hint**: Self-reduction occurs without the presence of air, allowing the reaction to proceed differently.

4. **Analyzing Statements**:
- **Statement P**: "Galena is a sulphide ore and therefore, it is concentrated by froth flotation process."
- This statement is **correct**.
- **Statement Q**: "Self reduction takes place in absence of air."
- This statement is **correct**.
- **Statement R**: "Complete roasting of galena gives PbO which is then reduced by coke or CO to give metallic lead."
- This statement is **correct**.
- **Statement S**: "`FeSiO_(3)` is obtained as slag."
- This statement is **incorrect** as `FeSiO_(3)` (silicate slag) is typically associated with the extraction of copper, not lead.

5. **Conclusion**:
- The correct statements about the extraction of lead from galena are P, Q, and R. Statement S is incorrect.

### Final Answer:
The correct statements regarding the extraction of lead from galena are P, Q, and R.