State two important uses of graphite.

Hint:On account of its microstructure made up of hexagonal planes of $s{p^2} - s{p^2}$ hybridized carbon bonds, graphite has a number of properties which find applications in a variety of fields. Since each carbon atom is bonded to only three carbon atoms one electron from each carbon atom is not bonded. It roams freely between the layers resulting in good electrical conductivity of graphite.

Complete step by step solution:
Graphite is an allotropic form of carbon and is an opaque substance which is greyish black in colour.
We know that in graphite, carbon forms triple bonded molecular lattice bonded by covalent bonds. The carbon atoms form layers having a hexagonal arrangement of atoms. These layers of carbon atoms are held together by weak intermolecular Van der Waals forces.
Since the interlayer bonds are very weak, the layers can slip easily over each other with a very low amount of friction. Thus, it is used as a dry lubricant in machineries as the layers cleave between the layers of the machinery and makes the surfaces soft and slippery preventing wear and tear.
Graphite is also used to increase the amount of carbon in molten steel. Graphite is cheap and easily available and thus it is efficient to use graphite as a carbon raiser.

Note:
Since the carbon atom in graphite has $s{p^2}$ hybridization and is bonded to three other carbon atoms resulting in the formation of hexagonal rings, each atom consists of an unhybridized p orbital which undergoes sideways overlapping forming three $p\pi - p\pi $ bonds with the three adjacent carbon atoms. As a result, graphite has a planar sheet like structure containing a number of hexagonal sheets fused together. This sheet-like structure makes it a soft material.