Introduction
Movement of ions , gases, solute from their higher concentration to lower concentration is called diffusion. Eg:- If a drop of ink is dropped into the glass containing water , very soon its molecules become distributed throughout the glass.
Experiment of diffusion
When a crystal of CuSO4 is placed in a beaker containing water, a dense blue color is sen around the crystal. It decrease with increase in distance from the Crystal representing the diffusion of the CuSO4 molecules moves towards water and water moves toward the CuSO4. Finally , the molecules of both water and CuSO4 are distributed equally throughout the solution.
Diffusion pressure
The pressure exerted by the diffusing ions or molecules to diffuse from the area of its higher concentration to lower concentration is called diffusion pressure.
Experiment of diffusion pressure:-
Fill a rubber ballon with any gas. The gas molecules are confined to space within the ballon and their molecules exerts a pressure on the wall of the ballon. Now, prick the ballon. Gases released immediately and collapsed the ballon. The pressure under which gas will release from the ballon represents the diffusion pressure.