Which of the following metals cannot be extracted by carbon reduction process?

Options

A. Pb
B. Al
C. Hg
D. Zn

Answer

To determine which of the following metals cannot be extracted by the carbon reduction process, we need to analyze the reactivity of each metal in relation to carbon.

### Step-by-Step Solution:

1. **Understanding Carbon Reduction Process**:
The carbon reduction process involves the reduction of metal oxides using carbon (in the form of coke or carbon monoxide). This process is applicable to metals that are less reactive than carbon.

2. **Analyzing the Metals**:
- **Lead (Pb)**: Lead is less reactive than carbon, so it can be extracted by carbon reduction.
- **Aluminium (Al)**: Aluminium is more reactive than carbon, meaning it cannot be reduced by carbon. Therefore, it cannot be extracted by this method.
- **Mercury (Hg)**: Mercury is also less reactive than carbon, so it can be extracted by carbon reduction.
- **Zinc (Zn)**: Zinc is less reactive than carbon, allowing for its extraction through carbon reduction.

3. **Conclusion**:
Among the given options, Aluminium is the only metal that cannot be extracted by the carbon reduction process due to its higher reactivity compared to carbon.

### Final Answer:
**Aluminium (Option 2)** cannot be extracted by the carbon reduction process.

---