Answer:
Coal gas is a flammable gaseous fuel made from coal and supplied to the user via a piped distribution system.It is produced when coal is heated strongly in the absence of air. ... Facilities where the gas was produced were often known as a manufactured gas plant (MGP) or a gasworks.
Coal tar is a thick dark liquid which is a by-product of the production of coke and coal gas from coal. It has both medical and industrial uses. Medicinally it is a topical medication applied to skin to treat psoriasis and seborrheic dermatitis (dandruff). It may be used in combination with ultraviolet light therapy.
: a bituminous coal suitable for making into coke.