How many of these metals carbon reduction is used during their extraction.
`Ag, Au, Fe, Sn, Zn, Pb, Al`

Answer

To determine how many of the metals listed (Ag, Au, Fe, Sn, Zn, Pb, Al) are extracted using carbon reduction, we will analyze each metal one by one.

1. **Silver (Ag)**: Silver is typically extracted using the cyanide process, not by carbon reduction.
- **Conclusion**: Not extracted by carbon.

2. **Gold (Au)**: Similar to silver, gold is also extracted using the cyanide process and not by carbon reduction.
- **Conclusion**: Not extracted by carbon.

3. **Iron (Fe)**: Iron is extracted from its ore (Fe2O3) using carbon in a blast furnace. The reaction can be represented as:
\[ \text{Fe}_2\text{O}_3 + 3\text{C} \rightarrow 2\text{Fe} + 3\text{CO} \]
- **Conclusion**: Extracted by carbon.

4. **Tin (Sn)**: Tin is extracted from its ore (SnO2) using carbon. The reaction is:
\[ \text{SnO}_2 + 2\text{C} \rightarrow \text{Sn} + 2\text{CO} \]
- **Conclusion**: Extracted by carbon.

5. **Zinc (Zn)**: Zinc is extracted from its ore (ZnO) using carbon. The reaction is:
\[ \text{ZnO} + \text{C} \rightarrow \text{Zn} + \text{CO} \]
- **Conclusion**: Extracted by carbon.

6. **Lead (Pb)**: Lead is extracted from its ore (PbO) using carbon. The reaction is:
\[ \text{PbO} + \text{C} \rightarrow \text{Pb} + \text{CO} \]
- **Conclusion**: Extracted by carbon.

7. **Aluminum (Al)**: Aluminum is extracted from its ore (Al2O3) using the Hall-Héroult process, which involves electrolysis rather than carbon reduction.
- **Conclusion**: Not extracted by carbon.

Now, summarizing the findings:
- Metals extracted by carbon reduction: Fe, Sn, Zn, Pb
- Metals not extracted by carbon reduction: Ag, Au, Al

Thus, the total number of metals that can be extracted using carbon reduction is **4** (Fe, Sn, Zn, Pb).

### Final Answer:
**4 metals (Fe, Sn, Zn, Pb) are extracted using carbon reduction.**