Question

Both coal and diamonds are forms of elemental carbon. Coal is brittle while diamonds are considered to be the hardest of all substances known. What is the appropriate justification for this?

Answer 1

Both coal and diamonds are allotropes of carbon , having different structures due to different arrangements of carbon atoms. 

Answer 2

Answer:

The correct explanation for this is that "both coal and diamond are the allotropes of the carbon due to which they exhibit different physical and chemical properties".

Allotropes refer to the property of some chemical compounds by which they can exhibit in two or more different forms. For example, graphite and diamond are allotropes of carbon.

Due to tetravalency, carbon is able to form such allotropes and due to the difference in chemical bonding such as bond length, bond angle, arrangements of carbon chains, et cetera these allotropes exhibit different physical and chemical properties.

For example, diamond is the hardest substance whereas coal is brittle in nature. Similarly, graphite is a good conductor of electricity whereas diamond is a bad conductor.