In order to refine "copper" it is melted in a furnace and it is stirred with green logs of wood. The purpose is :-

Options

A. to expel the dissolved gases in blister copper
B. to reduce the metallic oxide impurities with hydrocarbon gases liberated from the wood
C. to bring the impurities to surface and oxidise them
D. to increase the carbon content in copper

Answer

To refine copper, it is melted in a furnace and stirred with green logs of wood. The purpose of this process can be understood through the following steps:

### Step-by-Step Solution:

1. **Understanding Blister Copper**:
- Blister copper is an intermediate product obtained during the extraction of copper. It contains impurities and dissolved gases, primarily oxygen.

**Hint**: Remember that blister copper is not pure and contains various impurities.

2. **Melting in a Furnace**:
- The blister copper is melted in a furnace, specifically a reverberatory furnace. This allows for the separation of impurities from the copper.

**Hint**: Think about how melting can help in separating different components based on their physical properties.

3. **Stirring with Green Logs of Wood**:
- The addition of green logs of wood introduces hydrocarbon gases into the molten copper. These gases are produced from the combustion of the wood.

**Hint**: Consider what happens when wood burns and how it can affect the surrounding materials.

4. **Reduction of Copper Oxides**:
- Any copper oxides that may have formed during the melting process can be reduced back to metallic copper by the hydrocarbon gases released from the burning wood.

**Hint**: Recall that reduction reactions involve the gain of electrons or the removal of oxygen.

5. **Bringing Impurities to the Surface**:
- The stirring action helps to bring impurities to the surface of the molten copper, where they can be removed.

**Hint**: Think about how stirring can help mix substances and facilitate separation.

6. **Final Purpose**:
- The overall purpose of stirring with green wood is to refine the copper by reducing metal oxide impurities and expelling dissolved gases, resulting in purer copper.

**Hint**: Focus on the end goal of refining processes, which is to obtain a purer product.

### Conclusion:
The purpose of stirring blister copper with green logs of wood during the refining process is primarily to reduce the metal oxide impurities with hydrocarbon gases liberated from the wood. Therefore, the correct answer is **Option B**.