Question

The extremely high melting point of diamond (carbon) may be explained by the:
A. Network covalent bonds
B. Ionic bonds
C. Hydrogen bonds
D. Van der Waals forces
E. None of the above

Answer 1

Hint: Try to recall that diamond is a crystalline allotropic form of carbon and is the purest form of carbon. Also, in diamond each carbon is tetrahedrally linked to four neighbouring carbon atoms. Now, by using this you can easily answer the given question.

Complete step by step solution:
-It is known to you that carbon exists in two or more forms which have different physical properties but identical chemical properties and diamond is the purest form of carbon.
-It occurs in nature and can also be prepared artificially but because of high cost and poor quality, diamonds are seldom made artificially.
-Also, diamond has the highest thermal conductivity of any known substance although it is a bad conductor of electricity.
-In diamond, carbon atoms are sp³-hybridized. Each carbon atom is tetrahedrally linked to four neighbouring carbon atoms through four strong sigma covalent bonds. This network extends in three dimensions and is very rigid.
-Diamond exists as a three-dimensional network solid, so it is the hardest substance with high density and melting point.
Therefore, from above we can easily conclude that option A is the correct option to the given question.

Note:
- It should be remembered to you that diamond is a bad conductor of electricity because all the electrons are firmly held in C-C covalent bonds, so there are no free electrons in a diamond crystal.
- Also, you should remember that because of its hardness, diamond is used for cutting glasses.