Question

The variety of coal having maximum carbon content is
(A) peat
(B) anthracite
(C) bituminous
(D) lignite

Answer 1

Hint: Coal is a type of sedimentary rock having a very high amount of carbon content. The carbon content depends on the time taken by the coal to be formed. Carbon content decides the quality of coal and is different in different types of coal.

Complete step by step solution:
-Coal is a type of non-renewable energy source. It gives us energy when it is burnt. It contains carbon which burns to give us carbon-dioxide and other greenhouse gases.
-Coal was formed around 360 million years ago by the decaying of the dead plants in different layers over millions of years. The oxygen, nitrogen and moisture content reduced with time and the carbon content increased with time to produce coal.
-Duration and the heat intensity decide the percentage of the carbon content of coal. Coal is classified as bituminous, peat, lignite and anthracite based on the amount of carbon, oxygen, moisture and hydrogen present in the coal.
-Peat is the first stage of coal formation and so it is the worst variety of coal. It has a carbon content of around 40 to 55 percent only. Lots of impurities are present in this type of coal like moisture and volatile content. It burns like wood creating lots of ashes.
-Lignite is also known as brown coal and it is also lower grade coal with the carbon content ranging from 40 to 55 percent. Its name is given owing to the colour of this coal which is dark brown to black-brown in colour. It has high moisture content.
-Bituminous coal derives its name from bitumen which is a liquid. It is a soft coal with 40 to 80 percent coal and 15 to 40 percent moisture. So it is higher grade coal and is black in colour. This type of coal is dense and compact and is used for the purpose of coal in coke and gas production. It has a high calorific value.
-Anthracite coal is the best quality coal with carbon content ranging from 80 to 95 percent. It is hard and contains very little impurities of volatile matter and moisture. It ignites slowly thus releasing a large amount of energy on burning. It burns with a blue flame.

Therefore the correct option is (B).

Note: It is believed that the formation of coal takes place even today. Coal takes millions of years to form and so it is a non-renewable energy source. With time and pressure, peat converts to lignite, lignite to bituminous and bituminous to anthracite. Coal is used as a domestic fuel and as a source of electrical and steam energy.