The purest form of carbon is

Carbon exists in many forms, but not all are equally pure. Let’s examine the options and why diamond is the purest form of carbon.

1. Bituminous coal:
   Bituminous coal is a natural rock-like substance that contains a mix of carbon, hydrogen, sulfur, and other impurities. While it has a high carbon content, it is not pure carbon because of the presence of these additional elements.
2. Coal-tar:
   Coal-tar is a byproduct of coal processing and is a thick liquid. It contains a variety of organic compounds and is far from being pure carbon. This rules it out as the purest form of carbon.
3. Coal gas:
   Coal gas is a mixture of gases, including hydrogen, methane, and carbon monoxide, produced by heating coal. It is not a solid form of carbon and contains multiple other elements, making it impure.
4. Diamond:
   Diamond is a crystalline form of carbon where each carbon atom is tightly bonded to four other carbon atoms in a three-dimensional structure. This perfect arrangement makes it a highly stable and pure form of carbon. Unlike the other options, diamond contains no impurities or additional elements in its natural state. That is why diamond is considered the purest form of carbon.