Which of the following metals is not extracted by leaching ?

Options

A. Aluminium
B. Mercury
C. Silver
D. Gold

Answer

To determine which metal is not extracted by leaching, we need to understand the leaching process and the solubility of the ores of the metals in question.

### Step-by-Step Solution:

1. **Understand Leaching**: Leaching is a process used to extract metals from their ores by dissolving them in a suitable solvent. For leaching to be effective, the ore must be soluble in the solvent, while the impurities should remain insoluble.

2. **Identify the Metals**: The metals mentioned in the question are aluminum, silver, gold, and mercury. We need to analyze the solubility of their ores.

3. **Analyze Ores of Each Metal**:
- **Aluminum**: The ore of aluminum (bauxite) is soluble in sodium hydroxide solution, making it suitable for extraction by leaching.
- **Silver**: Silver ores (like argentite) can be dissolved in cyanide solution, allowing for extraction through leaching.
- **Gold**: Gold ores (like auriferous ores) are also soluble in cyanide solution, enabling their extraction via leaching.
- **Mercury**: Mercury ores (like cinnabar) are generally insoluble in most solvents, which means they cannot be effectively extracted by leaching.

4. **Conclusion**: Since aluminum, silver, and gold can be extracted through leaching due to their solubility in appropriate solvents, while mercury cannot be extracted by this method, the answer to the question is mercury.

### Final Answer:
The metal that is not extracted by leaching is **mercury**.

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