Liquid-liquid colloidal system in which finely divided droplets of a liquid are dispersed into other liquid are called emulsion.
Types of emulsions:
(i) Oil in water, e.g. milk.
(ii) Water in oil, e.g. butter

(i) NH₃ has higher critical temperature than N₂, i.e. NH₃ is more easily liquefiable than N₂. Hence, NH₃ has greater intermolecular forces of attraction and hence will be adsorbed more readily on the surface of charcoal.
(ii) Powdered substances have more surface area and the adsorption increases with increase in surface area of the adsorbent and hence, powdered substances are more effective adsorbents

Cationic detergents are quarternary ammonium salts of amines with acetates, chlorides or bromides as anions. The cationic part possesses a long hydrocarbon chain with a positive charge on nitrogen atom. e.g. cetyltrimethylammonium bromide used in hair conditioners.
\(\left[ { CH }_{ 3 }({ CH }_{ 2 })_{ 15 }-\overset { \begin{matrix} { CH }_{ 3 } \\ | \end{matrix} }{ \underset { \begin{matrix} | \\ { CH }_{ 3 } \end{matrix} }{ N } } \right] ^{ + }{ Br }^{ - }\)
(ii) Broad spectrum antibiotic Antibiotics which kill or inhibit a wide range of harmful or disease causing bacteria are called broad spectrum antibiotics. These are equally effective against gram-positive and gram-negative bacteria (both). e.g. ampicillin and amoxycillin.
(iii) Tranquiliser The chemical compounds which are used for the treatment of stress, mild and severe mental diseases are known as tranqulisers,
e.g. equanil. They form an essential component of sleeping pills

a) Silica gel is a good adsorbent and hence water vapour are adsorbed on its surface. Anhydrous CaCl₂ undergoes absorption because it combines with water molecules to form hydrated calcium chloride, CaCI₂. 2H₂O.
b) BF₃ acts as a strong Lewis acid and hence used as catalyst in industrial processes.

(a) NH3 will be adsorbed more readily on the surface of charcoal because it has higher critical temperature due to more van der Waals' forces of attraction.
(b)  

(c) Electrodialysis: It is based on the principle that ions can pass through parchment paper faster in the electric field than colloidal particles and thus, get separated.

(a) Pass a beam of light through it. If the path becomes clearly visible, ie. if it shows Tyndall effect, it is a colloidal solution. If the path of light is not visible, it is a true solution.
(b) (i) Chromatography is based on differential adsorption.
(ii) The charge on the colloidal solution is due to selective adsorption of common ions on the surface.
(iii) Heterogeneous catalysis is based,on adsorption of gases on solid.
(iv) Carbon particles from smoke get adsorbed on the surface of electrodes of Cottrell smoke pre