Lead obtained form galena `(PbS)` by air reduction or carbon reduction process contains base metal `(Cu, Bi, Sn, As)` as impurities, due to the which lead becomes hard and brittle.
Cupellation is used for purification of

Options

A. `Pb`
B. `Ag`
C. `Zn`
D. `Fe`

Answer

**Step-by-Step Solution:**

1. **Understanding the Context**: The question states that lead obtained from galena (PbS) contains impurities such as copper (Cu), bismuth (Bi), tin (Sn), and arsenic (As), which make lead hard and brittle.

2. **Identifying the Purification Process**: The process mentioned for the purification of lead is cupellation. Cupellation is a method used to separate noble metals from base metals.

3. **Defining Noble Metals**: Noble metals are metals that are resistant to corrosion and oxidation in moist air. Common examples include gold (Au) and silver (Ag).

4. **Identifying the Noble Metal in the Options**: The question asks which noble metal is purified using cupellation. Among the options provided, we need to identify which one is a noble metal.

5. **Analyzing the Options**:
- Gold (Au) is a noble metal.
- Silver (Ag) is also a noble metal.
- The other metals listed (Cu, Bi, Sn, As) are not noble metals.

6. **Conclusion**: Since cupellation is primarily used for the purification of noble metals, and among the options provided, the only noble metal mentioned is silver (Ag).

7. **Final Answer**: Therefore, the answer to the question is that cupellation is used for the purification of **silver (Ag)**.

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