Question

Which of the following names represents the foul smelling, black, thick, viscous liquid obtained from the destructive distillation of coal?
A.Coke
B.Coal tar
C.Coal gas
D.None of these

Answer 1

Hint: Destructive distillation is a process which involves the decomposition of unprocessed material under specific conditions of high temperature and a certain amount of pressure.

Complete step by step answer:
-Destructive distillation is often performed on organic materials, wherein the given organic material is processed in the presence of limited amounts of oxygen, as well as certain corresponding catalysts, reagents, and solvents. The result of destructive distillation can often be seen as the formation of various by-products from the given organic material. Many times, these products may or may not be desirable.
-Coal is a carbon-based substance, i.e. it is organic in nature. Destructive distillation of coal gives many by-products.
-The type of products that we may obtain largely depends on the temperature at which we process the coal. When the temperature is between 400 \[^\circ C\] and 500 \[^\circ C\], cola breaks down to form only some gases, certain oils and paraffins. When the temperature is further risen from 700 \[^\circ C\] to 800 \[^\circ C\], the resulting products consist of more gases, which majorly contain hydrogen. On further heating, we can observe the formation of gases such as hydrogen, methane, ethane and ethylene; whilst contact of these gases with the hot retort causes further splitting off of hydrogen and condensation of the nuclei into benzene, toluene, naphthalene, and anthracene, which are contained in the tar.
-This tar is the foul smelling, black, thick, viscous liquid obtained from the destructive distillation of coal.

Hence, Option B is the correct option.

Note:
The nitrogen of the coal remains in the coke, some appears as pyridine and quinoline in the tar, the rest as ammonia in ammoniacal liquor, as hydrocyanic acid and free nitrogen.