Explain the following :
a) Graphite is a good conductor.
b) Diamond has high melting point.

Explanation

a) Graphite has free p-electrons available. These electrons freely move throughout the crystal, lattice. Hence graphite acts as a good conductor.
In graphite each carbon atom is in sp hybridised, state.
b). Diamond is a three --dimensional giant molecule. The valency electrons of each carbon take part in bonding. The C-C bonds in it are very strong. Hence diamond has a high melting point (MP).