Question 1 What happens when coal is heated in air?
Question 2 Define the term destructive distillation of coal?
Question 3 What are the constituents of coal gas. State one use of coal gas?
Question 4 What is coal tar?
Question 5 State few uses of coal tar?
Question 6 What is coke?
Question 7 State few uses of coke?
Question 8 Why coke is a better fuel than coal?
Question 9 How is coke obtained?
Products of Coal
The various useful products obtained by processing the coal by heating in the absence of air are:
(1) Coal gas
(2) Coal tar
The strong heating of coal in the absence of air is called destructive distillation of coal.
If coal is heated in the presence of air, then coal burns to produce mainly carbon dioxide gas and no other useful products were obtained.
It is a gaseous fuel which is obtained by the strong heating of coal in the absence of air during the processing of coal to get coke.
(1) It is a mixture of methane and hydrogen, with some carbon dioxide.
(2) All the gases present in coal gas can burn to produce heat, due to which coal gas is an excellent fuel.
(3) It is used as a fuel in industries.
It is a thick, black liquid having an unpleasant smell which is obtained by heating coal in the absence of air.
(1) It is a mixture of about 200 carbon compounds or organic compounds.
(2) The useful carbon compounds present in coal tar includes benzene, toluene, naphthalene, anthracene, phenol and aniline.
(3) The various compounds present in coal tar are separated by the process of fractional distillation.
(4) The compounds obtained from coal tar are used as starting material for manufacturing a large number of substances used in everyday life and industry.
(5) The products of coal tar are used to make synthetic fibres, drugs, plastics, synthetic dyes, perfumes, paints, varnishes, pesticides, roofing material.
It is a tough and porous black solid substance.
It is prepared by heating coal in the absence of air.
(1) When coal is heated in the absence of air, then coal gas and coal tar are eliminated and coke is left behind as a black residue.
(2) Coke is an almost pure form of carbon. It is 98% carbon.
(3) It is mainly used as a reducing agent in the extraction of metals.
(4) It is used in the manufacture of steel.
(5) It is used as fuel.
(6) It is a better fuel than coal because it produces more heat on burning than an equal amount of coal. It burns without producing any smoke whereas coal produces a lot of smoke on burning.