Which of the following explain the poling process?

Options

A. Reduction of metallic oxide impurities to metal by Al
B. Reduction of metallic oxide impurities to metal by gaseous hydrocarbon
C. Electrolytic reduction of metallic oxide to metal
D. Removal of volatile oxide from the molten metal

Answer

To solve the question regarding the poling process, we need to understand what the process entails and how it is applied in metallurgy.

### Step-by-Step Solution:

1. **Definition of Poling Process**: The poling process is a method used to purify metals, particularly those that contain oxidized impurities. It is primarily applied to metals like copper and tin.

2. **Purpose of the Process**: The main purpose of the poling process is to remove oxidized impurities from these metals. This is crucial for obtaining high-purity metals suitable for various applications.

3. **Materials Used**: In the poling process, a log of green wood is typically used. The green wood contains hydrocarbons which play a significant role in the reduction process.

4. **Mechanism of the Process**: When the green wood is stirred into the molten metal, the hydrocarbons present in the wood act as reducing agents. They help in reducing the oxidized impurities present in the metal.

5. **Chemical Reaction**: During the process, the hydrocarbons reduce the metal oxides to their respective metals, while the oxygen from the oxides combines with carbon from the hydrocarbons to form carbon dioxide (CO2), which is released as a gas.

6. **Conclusion**: Therefore, the poling process effectively removes oxidized impurities from metals by converting them into gaseous CO2, leaving behind purified metal.

### Summary of Options:
- **Reduction of metallic oxide impurities to metal by aluminium**: Incorrect, as aluminium is not used in this process.
- **Reduction of metallic oxide impurities to metal by gaseous hydrocarbons**: Correct, as hydrocarbons from the green wood are used for reduction.
- **Electrolytic reduction of metal oxide to metal**: Incorrect, as this describes a different process.
- **Removal of volatile oxide from the molten metal**: Incorrect, as this does not accurately describe the poling process.

### Final Answer:
The option that correctly explains the poling process is: **Reduction of metallic oxide impurities to metal by gaseous hydrocarbons.**