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

### Step-by-Step Solution:

1. **Definition of the Poling Process**:
- The poling process is a method used to purify metals that have oxidized impurities. It is particularly effective for metals like copper, which often have copper oxide as an impurity.

2. **Understanding the Impurities**:
- In the case of copper, the common impurity is copper oxide (CuO). The goal of the poling process is to reduce this oxide back to pure copper metal.

3. **Role of Reducing Agents**:
- In the poling process, hydrocarbons (CxHy) are used as reducing agents. A reducing agent is a substance that donates electrons to another substance, causing the reduction of that substance.

4. **Chemical Reaction**:
- The reduction reaction can be represented as follows:
\[ \text{CuO} + \text{CxHy} \rightarrow \text{Cu} + \text{CO}_2 \]
- Here, copper oxide (CuO) is reduced to copper (Cu), while the hydrocarbon is oxidized to carbon dioxide (CO2).

5. **Evaluating Options**:
- When evaluating the options provided in the question:
- The first option states that the reduction is by aluminum, which is incorrect because aluminum is not used in the poling process.
- The second option correctly states that the reduction is by gaseous hydrocarbons, which aligns with the definition of the poling process.

6. **Conclusion**:
- Therefore, the correct explanation of the poling process is that it involves the reduction of metallic oxide impurities to metal by gaseous hydrocarbons.