In which of the following isolation no reducing agent is required

Options

A. Mercury from cinnabar
B. Zinc from zinc blende
C. Iron from haematite
D. Aluminium from Bauxite

Answer

To solve the question of which isolation process does not require a reducing agent, we will analyze the given options and the characteristics of each ore.

### Step-by-Step Solution:

1. **Identify the Ores**: The ores provided in the question are:
- Cinnabar (HgS)
- Zinc Blend (ZnS)
- Hematite (Fe2O3)
- Bauxite (Al2O3)

2. **Understanding Reducing Agents**: A reducing agent is a substance that donates electrons to another substance in a redox reaction, causing the other substance to be reduced. In some cases, certain metals can be extracted without the need for an external reducing agent due to their ability to undergo auto-reduction.

3. **Identify Auto-Reducible Elements**: The elements that can be auto-reduced (i.e., do not require an external reducing agent) are:
- Lead (Pb)
- Mercury (Hg)
- Copper (Cu)
- Tin (Sn)

4. **Analyze Each Ore**:
- **Cinnabar (HgS)**: Contains mercury, which can undergo auto-reduction.
- **Zinc Blend (ZnS)**: Zinc does not belong to the auto-reducible elements.
- **Hematite (Fe2O3)**: Iron does not belong to the auto-reducible elements.
- **Bauxite (Al2O3)**: Aluminum does not belong to the auto-reducible elements.

5. **Conclusion**: Among the given options, only Cinnabar (HgS) can be reduced without the need for an external reducing agent because it contains mercury, which is one of the auto-reducible elements.

### Final Answer:
Cinnabar (HgS) is the only ore listed that does not require a reducing agent for its isolation.

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