What is destructive distillation of coal ? Describe the constituents obtained from this process.
Burning of coal in absence of air to obtain some useful constituents is called destructive Distillation. Following constituents are obtained from this process :
(i) Coke : It is a hard porous substance which is almost the purest form of carbon. It is used in manufacture of steel and in extraction of many metals.
(ii) Coal-tar : It is a black liquid with unpleasant smell. It is a mixture of about two hundred substanes which are very useful in our day to day life. They are used in drugs, plastics, paints, photographic materials, synthetic dyes, roofing materials, perfumes, explosives etc. Insect repellants like naphthalene is also obtained from it. Earlier, it was also used for surfacing of roads.
(iii) Coal gas : This gas is also obtained during destructive distillation of coal. It is used as fuel in coal processing plants and in various other industrial units situated near coal processing plants. Coal gas was used by the Americans and the Britishers for street lighting.
What are the advantages of using CNG and LPG as fuels?
Advantages of CNG—Compressfed Natural Gas and LPG—Liquefied Petroleum Gas are:
i) Both fuels burn with clean flame that does not produce smoke.
ii) They give more heat and energy as compared to other fuels.
Fossil fuels are ________, ________ and ________.
Name the petroleum product used for surfacing of roads.
Bitumen or coaltar is used for surfacing of roads.
Describe how coal is formed from dead vegetation. What is this process called?
Millions of years ago, dense forest and animal got buried under the soil due to natural process like floods, earthquakes and thunder storms. When they got buried deep in the soil, they were exposed to very high pressure and temperature. Under these conditions, these slowly got converted into coal. This process of formation of coal vegetation is called carbonization.
Process of separation of different constituents from petroleum is called __________.