Solution:

Coal is also called black gold. Coals are classified into Peat, Lignite, Bituminous, and Anthracite.

Lignite:

– Brown coal

– Lower grade coal

– Moisture content is high (over 35 percent)

Bituminous Coal:

– Soft coal; most widely available and used coal.

– Derives its name after the liquid called bitumen

– 40 to 80 percent carbon

– Moisture and volatile content (15 to 40 percent)

Anthracite Coal:

– Best quality; hard coal.

– 80 to 95 percent carbon.

–
Very little volatile matter

– Negligibly small proportion of moisture