The black thick liquid with unpleasant smell is known as _______ .

Options

A. kerosene
B. coal-tar
C. petrol
D. coke

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a specific black thick liquid that has an unpleasant smell.

2. **Identifying the Source**: The black thick liquid in question is derived from the process of destructive distillation of coal.

3. **Products of Destructive Distillation**: During the destructive distillation of coal, several products are formed, including:
- **Coke**: A solid product used as a fuel.
- **Coal Tar**: A thick black liquid with a strong, unpleasant smell.
- **Coal Gas**: A gaseous product used as a fuel.

4. **Identifying the Correct Product**: Among the products listed, coal tar is the only one that is a black thick liquid and has an unpleasant smell.

5. **Conclusion**: Therefore, the answer to the question is "coal tar".

**Final Answer**: The black thick liquid with an unpleasant smell is known as **coal tar**.

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