The Solid State

Question 5

Refractive index of a solid is observed to have the same value along all directions. Comment on the nature of this solid. Would it show clevage property?

Refractive index of a solid which have the same value along all directions are isotropic in nature. It would not show cleavage property.
Question 6

Classify the following solids in different categories based on the nature of intermolecular forces operating in them:
Potassium sulphate, tin, benzene, urea, ammonia, water, zinc
sulphate, graphite, rubidium, argon, silicon carbide.


Molecular solids: water, argon.
Ionic solids: potassium sulphate, zinc sulphate.
Metallic solids: tin, rubidium.
Covalent or network: benzene, urea, ammonia, graphite, silicon carbide.

Question 7

Solid A is a very hard, electrical insulator in solid as well as in molten state and melts at extremely high temperature. What type of solid is it?

It is covalent or network solid.
Question 8

Ionic solids conduct electricity in liquid state but not in solid state. Explain.


Ionic solids do not conduct electric current in solid state because in the solid ionic compound, the ions are held together in fixed positons by strong electrostatic forces and cannot move freely.
Ionic solids conduct electricity in liquid state because the crystal structure is broken down and ions become free to move and conduct electricity.

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