Refining of tin cannot be done by :

Options

A. cupellation
B. liquation
C. poling
D. electrorefining

Answer

To determine which refining process cannot be used for tin, let's analyze the options given: cupellation, liquefaction, pooling, and electro refining.

### Step-by-Step Solution:

1. **Understanding the Refining Processes:**
- **Cupellation:** This process is used to separate metals from their ores based on their melting points. It involves heating the metal with impurities until it melts, allowing the impurities to be oxidized and removed. However, this process is not suitable for metals with low melting points.
- **Liquefaction:** This process is effective for separating metals from impurities when the impurities have a higher melting point than the metal itself. In liquefaction, the metal melts and can be poured off, leaving the impurities behind.
- **Pooling:** This method involves stirring a mixture of metal and coke in a container to prevent oxidation. It can be used for refining metals, including those with low melting points.
- **Electro Refining:** This process uses an electrolytic cell where impure metal is placed at the anode and pure metal is deposited at the cathode. It is suitable for refining metals, including tin.

2. **Analyzing Tin's Properties:**
- Tin has a low melting point (about 232°C). This characteristic is crucial in determining the suitable refining process.

3. **Identifying the Unsuitable Process:**
- **Cupellation** is not suitable for tin because, during the process, the low melting point of tin means that it will melt and mix with the impurities rather than separate from them. Therefore, it cannot effectively refine tin.

4. **Conclusion:**
- The refining process that cannot be used for tin is **Cupellation**.

### Final Answer:
The refining of tin cannot be done by **Cupellation**.