A colloid solution is a heterogeneous mixture whose dispersed particles are larger than molecules but smaller than what can be seen with the naked eye, ranging from 1-1000 nm. Colloids exhibit unique optical properties like the Tyndall effect where a beam of light is scattered when passing through the colloidal solution. Colloids can be classified as hydrophilic or hydrophobic depending on whether the particles are attracted to or repelled by water. Common examples are emulsions like milk or gels.

1. Sabrya jarjess zuber
colloid solution

2. What is a colloid solution?
Colloids are mixtures whose particles are larger than the size of a
molecule but smaller than particles, size varies between 1 and 1000
that can be seen with the naked eye. Colloids are one of three major
types of mixtures, the other two being solutions and suspensions.

3. colloids can be classified
1. Hydrophilic colloids:These are water-loving colloids.
The colloid particles are attracted toward the water.They
are also called reversible sols.
2. Hydrophobic colloids:These are opposite in nature to
hydrophilic colloids.The colloid particles are repelled by
water.They are also called irreversible sols.

4. Properties of Colloidal system
 One property of colloid systems that distinguishes them from true solutions is that
colloidal particles scatter light
 If a beam of light, such as that from a flashlight, passes through a colloid, the light is
reflected (scattered) by the colloidal particles and the path of the light can therefore be
observed.
 The best example to prove their familiarity with us is that we know from very early
times that coagulation of milk results in the formation of curd.

5. Phases of colloids
1- Internal phase or Dispersed phase (Discontinuous phase)
It is the component present in small proportion and is just like a solute in a solution.
For example in the colloidal solution ofacts as a dispersed phase).
Phases of colloids: We know that a colloidal solution is of heterogeneous
nature. It consists of two phases which are as follows

6. Phases of colloids
2- External phase or Dispersion
medium (continuous phase) :
It is generally component present in
excess and is just like a solvent in a
solution.
For example, in the colloidal solution of
silver in water.Water act as a dispersion
medium.

7. Types of the colloidal system depending on the
dispersion medium and dispersal phase:
1- Gel: are the types of colloids in which the dispersed phase is a liquid
and the dispersion medium is a solid.
2- Sol: are the types of colloids in which the dispersed phase is a solid
and the dispersion medium is a liquid.

8. Properties of Colloidal Solutions
All the properties of colloidal solutions can be grouped under two
heads:
General Properties:
Optical Properties

9. General Properties:
 The particles of the dispersed phase are relatively large;
however, they pass through ordinary filter media.
 The dispersed phase doesn’t dissolve in the dispersion
medium.
 Particles adsorb ions. (its own ions in preference to
others).
 When the particles of the dispersion phase join together,
they coagulate and separate due to gravity.
 Particles have large surface area.

10. Optical Properties:-
 2- Tyndall phenomena
TheTyndall Effect is the effect of light scattering in many directions
in colloidal dispersion, while showing no light in a true solution.
Tyndall effect, also called Tyndall phenomenon, scattering of a
beam of light by a medium containing small suspended particles
E.g; smoke or dust in a room, which makes visible a light beam entering
a window.
The effect is named for the 19th-century British physicist
John Tyndall, who first studied it extensively.

11. Tyndall phenomena
 To be classified colloidal, a material must have one or
more of its dimensions (length, width, or thickness)
in the approximate range of 1-1000 nm

12. Tyndall phenomena
 For example, light being shined through water and milk.The light is
not reflected when passing through the water because it is not a
colloid. It is however reflected in all directions when it passes
through the milk, which is colloidal.

13. Tyndall phenomena

14. EXP.NO. 1: Phases reversal in hydrophilic colloidal solution
Procedure
 Put small amount of the liquid agar in test tube or beaker and put it in a cold mixed
, allow 10 minuet or more after that record the result put the tube or beaker with
its frizzed agar in warm water or in water bath , what happen to agar?
 Get small amount of egg albumen , put it in boiling water tube or beaker , record
the result ?put the tube or beaker with its continent in cold mixed , record what
happen to egg albumen at the last treatment?
 Make comparative between solution No. 1 and solution No. 2.
EXP.NO. 2:Tyndall phenomena
Procedure
 Prepare starch or gelatin solution and put it in a glass beaker (colloidal
solution) and put the beaker in dark field or case from carton.
 Illuminate one side of the case by strong light beam.
 Prepare salt solution and put it in a glass beaker (true solution), and put the
beaker in dark field or case from carton.
 Make comparative between colloidal solution and true solution with
explanation.