Question

define diffusion explain the rate of order of diffusion in solids liquids and gases

Answer 1

The intermixing of particles on their own is called diffusion.
In solids it is less because the inter molecular spaces are less.
In liquids it is slightly more because the spaces are more as compared to that of solids.
In gases it is the most because the inter molecular space is very large.

Answer 2

Diffusion is the state where molecules move from higher concentration level to lower concentration level till both the concentrations are same. DIffusion is highest in gases. Diffusion in solids is very slow as the particles are tightly packed.