Chapter 1 of NCERT Solutions for Class 12 Chemistry examines the properties of solids, which are one of the three states of matter, alongside liquids and gases. The key characteristics of solids discussed in the chapter are as follows:

1. Solids have a definite mass, shape, and volume.
2. Intermolecular distance in solids is short, while intermolecular force is strong.
3. Solids are rigid and difficult to compress.
4. The particles in solids occupy fixed positions.