(a) A Solid- (i) Solids have a definite shape, distinct boundaries and fixed volumes, that is, they have negligible compressibility.

(ii) Solids may break under force but it is difficult to change their shape, so they are rigid.

(b) A Liquid- (i) liquids have no fixed shape but have a fixed volume

(ii) The rate of diffusion of liquids is higher than that of solids.

(c) A Gas-(i) Gases are highly compressible as compared to solids and liquids.

(ii) Due to high speed of particles and large space between them, gases show the property of diffusing very fast into other gases.