1. BY:BY: 2 K 7 - A V - 3 1 2 K 7 - A V - 3 1

2. The Colloidal State The word colloid means glutinous,which do not diffuse through most of the membrans. This property is only determined by the size of the solute particles. Solution: The homogenous mixture of solute and solvent. Solute: Substance present in lesser quantity in the solution. Solvent: Substance present in higher quantity in the solution.

3. True Solution ParticlesColloidal ParticlesSuspension Particles < 1 nm1 to 100 nm> 100 nm Invisible even under microscope Visible under microscope Visible under microscope or even under naked eye Never settle out Do not settle but can be separated by various method Settle spontaneously Classification Of Particles

4. Types of Colloidal Solution Lyophobic colloids (liquid-hating): Colloidal metals such as gold,silver in water make make such solution. & have no affinity. Lyophillic Colloids (liquid-loving): These are more stable then lyophobic colloids. The lyophilic colloid particles have a charge but in addition they are surrounded by a very tightly bounded layer of the solvent. & have affinity.

5. Separation of Colloidal Particles 1- Electrophoresis: If an electrical current is passed through a colloidal solution, the particles being charged will travel to the oppositely charged electrode.

6. Separation of Colloidal Particles 2- Ultracentrifugation: It is a separation of the colloidal particles by subjecting them to a force of several thousands or even hundreds of thousands of gravity in a special apparatus called ultracentrifuge.

7. Separation of Colloidal Particles 3- Ultrafiltration: It is the process of filtration under pressure. Solution moves by pressure gradient

8. Separation of Colloidal Particles 4- Dialysis: Removal of waste products (urea) from the body through artificial kidney in case of renal failure. Types: Haemodialysis, Peritoneal Dialysis

9. Separation of Colloidal Particles 5- Adsorption: A process that occurs when a gas or liquid solute accumulates on the surface of a solid or a liquid (adsorbent), forming a molecular or atomic film (the adsorbate).

10. Properties of Colloidal Solution 1- Sols and Gels: A colloidal solution (Liquid) when exist is solution form is called a sol. When it exists in semi-solid form it is called gel.

11. Properties of Colloidal Solution 2- Thixotropy: The reversible sol – gel transformation 3- Imbibition: The process by which dry protein take up water and retain it. Plasma albumin can hold 17 ml water per gram.

12. Properties of Colloidal Solution 4- Brownian Movement: Zig-zag motion of colloidal particles in soluution.

13. Properties of Colloidal Solution 5- Tyndall effect: In ultramicroscope an intense beam of light is passed through the colloidal solution. Then colloidal particles appear as bright spots against dark background.