Explanation
Coal is processed in industries to obtain useful derivatives such as coke, coal tar, and coal gas. These by-products serve as raw materials for various industrial and domestic applications.Analysis of Options:
- Coal Tar: This is a thick, black liquid with an unpleasant smell. It is a mixture of about 200 substances. Naphthalene balls, which are widely used as moth repellents and insecticides, are obtained from coal tar.
- Coke: This is a tough, porous, and black substance. It is an almost pure form of carbon and is primarily used in the manufacture of steel and the extraction of many metals.
- Coal Gas: This is obtained during the processing of coal to get coke. It is mainly used as a fuel in industries situated near coal processing plants.
- Petroleum Jelly: This is a by-product of petroleum refining (crude oil), not coal. It is commonly used in cosmetics and medicinal ointments.
Key Takeaway: Naphthalene is an aromatic hydrocarbon derived specifically from coal tar, a by-product of coal processing.