(i) Emulsions are used in food industries. Food stuff like milk, cream, butter, etc., are emulsions.
(ii) Emulsions are very common in pharmaceutical industries. Many medicines are produced in the form of emulsions. Ex: Milk of magnesia is used for stomach troubles. Many lotions and ointments are emulsions.
(iii) Non ionic emulsions are most popular due to their low toxicity.
(iv) Cationic emulsions have anti microbial properties.
(v) In agriculture industry emulsions are used as delivery vehicles for insecticides, fungicides and pesticides.
(vi) In cosmetics, emulsions are the delivery vehicles for many hair and skin conditioning agents.
(v) The blood, protoplasm in plant and animal cells and fats in intestines are emulsions.

Factors affecting adsorption
Qualitatively, the extent of surface adsorption depends on
(i) Nature of adsorbent
(ii) Nature of adsorbate
(iii) Pressure
(iv) Concentration at a given temperature.
1. Surface area of adsorbent:
As the adsorption is a surface phenomenon it depends on the surface area of adsorbent. i.e., higher the surface area, higher is the amount adsorbed.
2. Nature of adsorbate:
The nature of adsorbate can influence the adsorption. Gases like SO₂, NH₃, HCl and CO₂ are easily liquefiable as have greater vander waal's force of attraction. On the other hand, permanent gases like H₂, N₂ and O₂ cannot be liquefied easily. These permanent gases are having low critical temperature and adsorbed slowly, while gases with high critical temperature are adsorbed readily.
3. Effect of temperature:
When temperature is raised chemisorption first increases and then decreases. whereas physisorption decreases with increases in temperature.
4. Effect of Pressure:
Chemical adsorption is fast with increase in pressure, it cannot alter the amount of adsorption. In physisorption, the extend of adsorption increases with increase in pressure.

(i) Certain substances when added to a catalysed reaction decreases or completely destroys the activity of catalyst and they are often known as catalytic poisons.
For example,
(ii) In the reaction, 2SO₂ + O₂ ⟶ 2SO₃ with a Pt catalyst, the poison is As₂O₃
(iii) i.e., As₂O₃ destroys the activity of Pt. As₂O₃ blocks the activity of the catalyst. So, the activity is lost.

A sol is electrically neutral. Hence the medium carries an equal but opposite charge to that of dispersed particles. When sol particles are prevented from moving, under the influence of electric field the medium moves in a direction opposite to that of the sol particles. This movement of dispersion medium under the influence of electric potential is called electro osmosis.