Question

A hard substance melts at high temperature and is an insulator in both solid and in molten state. This solid is most likely to be a/an:

• A. Metallic solid
• B. Covalent solid
• C. Ionic solid
• D. Molecular solid

Answer 1

The correct option is B Covalent solid

Answer: (2)

If a substance is an insulator in both solid and molten phases, then it can't be ionic or metallic solid.
f the melting point is higher, then it can't be a molecular solid.
It should be covalent networked solid.

Covalent bonds are strong and directional in nature, therefore atoms are held very strongly at their positions. Such solids are very hard and brittle. They have extremely high melting points and may even decompose before melting. They are insulators and do not conduct electricity (except graphite).