Why can’t aluminium be reduced by carbon ?

Answer

### Step-by-Step Solution:

1. **Understanding the Electropositivity of Aluminium**:
- Aluminium is classified as an electro-positive element, meaning it has a strong tendency to lose electrons and form positive ions. This property is crucial when considering reduction reactions.

2. **Comparison with Carbon**:
- Carbon is less electro-positive than aluminium. In a reduction reaction, a reducing agent must be able to donate electrons to the species being reduced. Since aluminium is more electro-positive, it has a greater tendency to lose electrons compared to carbon.

3. **Reducing Agent Concept**:
- A reducing agent is a substance that donates electrons in a chemical reaction. In this case, aluminium acts as a better reducing agent than carbon. Therefore, carbon cannot effectively reduce aluminium ions to metallic aluminium.

4. **Affinity for Oxygen**:
- Aluminium has a high affinity for oxygen. When aluminium is exposed to oxygen, it readily reacts to form aluminium oxide (Al₂O₃), also known as alumina. This reaction further demonstrates aluminium's inability to be reduced by carbon, as it prefers to bond with oxygen instead.

5. **Implications for Smelting Processes**:
- In industrial processes such as smelting, carbon is typically used to reduce metal oxides to their respective metals. However, since aluminium cannot be reduced by carbon, alternative methods such as electrolysis are employed to extract aluminium from its ores.

### Conclusion:
Aluminium cannot be reduced by carbon because it is more electro-positive than carbon, making it a better reducing agent. Additionally, aluminium's strong affinity for oxygen leads it to react with oxygen rather than being reduced by carbon.

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