Question

The high melting and boiling points of diamond are due to:
A. Its high refractive index
B. Its high IP value
C. Giant polymer structure with strong covalent bonds
D. Its high electronegativity

Answer 1

Hint: Melting point and boiling point of any compound depends upon the force of attraction between the constituent particles it consists of. Higher the force of attraction, higher will be its melting and boiling point. And in diamond, each carbon atom is bonded to four other carbon atoms, requiring a lot of thermal energy to break these atoms. So, choose the relevant option that satisfies this criterion.

Complete step by step solution:
Diamond is a mineral composed of pure carbon. It is known as the hardest naturally occurring substance and also the most popular gemstone. Because of their extreme hardness, diamonds have a number of important industrial applications.
Coming to its structure, diamond has a polymeric structure with multiple carbon-carbon single covalent bonds. Each carbon is covalently bonded to four other carbon atoms. So, the bond energy of each carbon-carbon single bond is very high.

To melt diamond, these covalent bonds are to be broken to increase the intermolecular separation. As diamond contains many covalent bonds (considered as the strongest bond among other bonds), high temperature is required to break such strong bonds. So, diamond melts and boils at a very high temperature.

Hence, the correct option is C.

Note: A covalent bond is formed by equal sharing of electrons from both the participating atoms. The electrons shared during this bonding are called a shared pair or bonding pair of electrons. The covalent bonds are also called molecular bonds.