It is a tough, porous, and black substance.
Explanation
Coal is processed in the industry to obtain useful products such as Coke, Coal Tar, and Coal Gas. This process, known as destructive distillation, involves heating coal in the absence of air, resulting in residues with distinct physical and chemical properties.Analysis of the Options:
- It is a tough, porous, and black substance. is Correct: Coke is a tough, porous, and black substance. It is an almost pure form of carbon. Due to these properties, it is an essential raw material used in the manufacture of steel and in the extraction of many metals.
- It is a viscous liquid with a pleasant odour. is Incorrect: A thick, black liquid with an unpleasant smell is characteristic of Coal Tar, which is a mixture of about 200 substances used for manufacturing dyes, drugs, and explosives.
- It is a gaseous fuel lighter than air. is Incorrect: The gaseous fuel obtained during the processing of coal to get coke is Coal Gas. It is used as a fuel in industries situated near coal processing plants.
- It is a soft, waxy solid. is Incorrect: Soft, waxy solids are typically associated with petroleum refining by-products (such as paraffin wax), not the primary by-products of coal distillation.
Key Takeaway: Coke is the solid, carbon-rich, porous residue obtained from coal processing, primarily utilized as a reducing agent in metallurgy.