A hard substance melts at high temperature and is an insulator in both solid and molten state. This solid is most likely to be a/an:
A hard substance melts at high temperature and is an insulator in both solid and molten state. This solid is most likely to be a/an:
The correct option is B Covalent Solid
Explanation for the correct option:
Covalent solids are composed of atoms covalently bonded to each other.
Due to the strength of covalent bonds, these solids have a high melting point.
Covalent compounds do not have free electrons between them so they act as insulators.
Therefore, option B is correct.
Explanation for incorrect options:
A) Metallic solids are hard but are good conductors of electricity. So they cannot be insulators. Hence, option A is incorrect.
C) Similarly, Ionic solids are also good conductors of electricity. Hence, option C is also incorrect.
D) Molecular solids are bonded by weak van der Waals forces, they are weakly bonded so they cannot have a high melting point. Hence, option D is incorrect.
Covalent Solid
Explanation for the correct option:
Covalent solids are composed of atoms covalently bonded to each other.
Due to the strength of covalent bonds, these solids have a high melting point.
Covalent compounds do not have free electrons between them so they act as insulators.
Therefore, option B is correct.
Explanation for incorrect options:
A) Metallic solids are hard but are good conductors of electricity. So they cannot be insulators. Hence, option A is incorrect.
C) Similarly, Ionic solids are also good conductors of electricity. Hence, option C is also incorrect.
D) Molecular solids are bonded by weak van der Waals forces, they are weakly bonded so they cannot have a high melting point. Hence, option D is incorrect.
