A porous black substance used in the extraction of metals is

Options

A. sodium
B. calcium
C. lead
D. coke

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a porous black substance that is used in the extraction of metals. We need to identify the correct substance from the given options.

2. **Identifying the Substance**: In metallurgy, particularly in the extraction of iron, a substance known as coke is commonly used. Coke is a porous black material derived from coal and is essential in the reduction of metal oxides.

3. **Role of Coke in Metal Extraction**: Coke serves two primary purposes in the extraction of metals:
- It acts as a reducing agent, which means it helps to convert metal oxides (like iron oxide) into the metal itself (like iron).
- It provides the necessary heat energy required for the extraction process when burned in a blast furnace.

4. **Analyzing Options**:
- **Option 1: Sodium** - Sodium is a silvery-white metal, not a black substance. Therefore, this option is incorrect.
- **Option 2: Calcium** - Calcium is also a silvery-white metal, which makes this option incorrect as well.
- **Option 3: Lead** - Lead has a bluish-white color and is not a black porous substance, thus this option is incorrect.
- **Option 4: Coke** - Coke is indeed a porous black substance used in the extraction of metals, making this the correct option.

5. **Conclusion**: Based on the analysis, the correct answer to the question is **Coke**.

**Final Answer**: A porous black substance used in the extraction of metals is **Coke**.

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