Question

Varieties of coal differ in:
(A) moisture
(B) volatile matter
(C) their carbon content
(D) all the above

Answer 1

Hint:The coal is the sedimentary type of the hard rock that is burned to give a solid fossil fuel. The most important content in the coal is carbon other than this hydrogen, Sulphur, nitrogen and the oxygen are also there. This rock of the coal is formed from the peat due to the pressure provided on the top of the rock.

Complete step by step solution:
The process in which the coal is formed is coalification, in which the buried plant materials are converted into sedimentary rock. This is classified into four types as anthracite, bituminous, sub bituminous and lignite. All these types differ from one other by the physical parameters like moisture, carbon content and the volatile matter.


Anthracite is the coal that ranks highest and it is hard, brittle and lustrous in nature. It possesses more carbon and less volatile matter. Bituminous has a high heating value and the subbituminous coal is very black and dull in appearance. The lignite is also called brown coal and it is considered as the lowest grade coal with the lowest percentage of the carbon in it.


Thus the option (D) is correct.


Note:The Bituminous coal used mainly as the fuel to generate the electric power, especially in the United States. The process of generating electricity is made by burning and converting water to steam that is used to drive the turbine which in turns produces electric power.