EVERYDAY SCIENCE

Detailed explanation-1: -Anthracite: The highest rank of coal. It is a hard, brittle, and black lustrous coal, often referred to as hard coal, containing a high percentage of fixed carbon and a low percentage of volatile matter. Bituminous : Bituminous coal is a middle rank coal between subbituminous and anthracite.

Detailed explanation-2: -Anthracite is hard as it contain around 86percent carbon and few volatile impurities and moisture. It is the highest rank of coal, hardest, glossy black used primarily for residential and commercial space heating.

Detailed explanation-3: -Anthracite is the hardest type of coal; it has the highest heating value and lowest moisture and ash content. It also has very little amount of volatile impurities and hence tends to burn without a flame. The carbon percentage in anthracite usually varies from 87% to 98%.

Detailed explanation-4: -Anthracite differs from ordinary bituminous coal by its greater hardness (2.75–3 on the Mohs scale), its higher relative density of 1.3–1.4, and luster, which is often semi-metallic with a mildly green reflection. It contains a high percentage of fixed carbon and a low percentage of volatile matter.

Detailed explanation-5: -Hence, lignite is the softest while anthracite is the hardest variety of coal. Q.