CBSE Class 12th Chemistry Chapter1 The Solid State -Part12

Class XII Chemistry Chapter 1 The Solid State NCERT Solution is given below.

Question 1.1:
Why are solids rigid?
Answer
The intermolecular forces of attraction that are present in solids are very strong. The constituent particles of solids cannot move from their positions i.e., they have fixed positions. However, they can oscillate about their mean positions. This is the reason solids are rigid.

Question 1.2:
Why do solids have a definite volume?
Answer
The intermolecular forces of attraction that are present in solids are very strong. The constituent particles of solids have fixed positions i.e., they are rigid. Hence, solids have a definite volume.

Question 1.3:
Classify the following as amorphous or crystalline solids:
Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl
chloride, fibre glass, copper.
Answer
Amorphous solids
Polyurethane, teflon, cellophane, polyvinyl chloride, fibre glass
Crystalline solids
Naphthalene, benzoic acid, potassium nitrate, copper