Question

When a diamond is heated to 1500, in the absence of air, it forms :
a.) graphite
b.) carbon black
c.) soot
d.) coke

Answer 1

Hint: Diamond is formed from carbon atoms which are arranged in the form of layers that have a uniform and a unique structure. The diamond crystals are packed in hexagonal close packing. When a diamond is heated in absence of air, it converts into another form of carbon which also has a layered structure. The newly formed structure is present in pencils and even can conduct electricity to some extent.

Complete Solution :
- Diamond is one of the precious stones that everyone desires to have. It is also very expensive in terms of money. If we see diamond from the eye of a chemist, then it is composed of carbon atoms which are arranged in layers.
- So, chemically diamond is composed of carbon atoms. The reaction given to us in question is the heating of carbon atoms in absence of oxygen.
- The reaction is given as -
$C(diamond)\xrightarrow[{in{\text{ absence of air}}}]{{1500}}C(graphite)$

So, when the diamond is heated in absence of air, we get graphite.
So, the correct answer is “Option A”.

Note: It must be noted that the diamond is a solid form of carbon. It has the highest thermal conductivity. It is the highest hardness known till now. Diamond is very useful. The most common use is as gemstones, they are used for adornment. These are used as abrasives for cutting hard materials in industries. Normally diamonds are mined from the Earth but these can also be synthesized in the laboratory but the process is not so easy.