The correct option is (c) 1 and 3 only.
Explanation
The destructive distillation of coal, a process where coal is heated strongly in the absence of air. This industrial process yields valuable by-products including coke, coal tar, and coal gas, each having distinct physical and chemical properties.
Statement-wise Analysis
- Statement 1 is Correct.
Coke is a tough, porous, and black substance. It is produced by removing volatile impurities from coal and represents an almost pure form of carbon. It is extensively used in the manufacture of steel and in the extraction of many metals. - Statement 2 is Incorrect.
Coal tar is not a pure substance; it is a thick, black liquid with an unpleasant smell. It is a mixture of about 200 different carbon compounds (including aromatics like benzene, naphthalene, and phenols). It is used as a starting material for manufacturing synthetic dyes, drugs, explosives, perfumes, and plastics. - Statement 3 is Correct.
Coal gas is obtained during the processing of coal to get coke (destructive distillation). While the primary residue of this process is coke, coal gas and coal tar are produced simultaneously as by-products. It was historically used for street lighting and is now used as a fuel in industries situated near coal processing plants.
Key Takeaway
Destructive Distillation of Coal:
- Coke: Solid residue, almost pure carbon (Fuel/Reducing agent).
- Coal Tar: Liquid mixture of organic compounds (Industrial raw material).
- Coal Gas: Gaseous fuel.