Question: Which of the following is the purest form of coal?
a) Peat
b) Lignin
c) Bituminous
d) Anthracite


Answer: d) Anthracite

All the above-mentioned options expect b) Lignin are the forms of coal. The percentage of coal contained in each one of them differentiates them from one another.

Anthracite contains the highest percentage of coal whereas Lignite consists the least.

Following is the percentage composition of coal in each of its above mentioned forms:
  1. Anthracite (86% to 97%)
  2. Bituminous (45% to 86%)
  3. Peat (<60%)
  4. Lignite (25% to 35%)
Lignin is not a form of coal. It is an organic polymer which is used in the formation of cell wall.

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