Explanation
Negatively colloid is coagulated by positive ion or vice-versa.
Coagulating power ∝ charge of coagulating Ion.
Emulsion stabilizing substances are called emulsifiers.
Example :- Agar , soap etc.
Milk is an emulsion not emulsifier.
In Gel, dispersed phase is liquid , dispersion medium is solid.
Dispersed phase is present throughout in the continuous.
Colour of colloidal solution is due to scattering of light by its particles.
In cottrell’s precipitator neutralisation of charge occurs. So the basic principle involved is neutralisation of charge on colloidal particles.
Colour of sky is due to scattering of light (Tyndall effect).
Alloy is a mixture of two or more elements.
Size :-
Suspension — >100 nm.
Colloids — 1nm – 100 nm.
True solution — < 1nm.
Colloids show Tyndall and Brownian effect.
One Pb2+ can coagulate two moles of [AgI] I –
Gelatin has the least Gold number.
Lyophilic colloids form colloidal solution contact with water. Starch is an example of lyophilic colloid.
As particle Size increases, colour of Gold sol changes form red to blue and finally Golden.
Process of conversion of a suspension into colloidal particles by adding suitable electrolyte is known as peptisation.
Change of colloidal state to suspension state is known as flocculation. Flocculation power increases with valency of ion of electrolyte.
Sol = dispersed phase is solid.
dispersion medium – liquid.
Size of colloidal particles — 100 nm – 1nm.
Colloidal solution is prepared by electrical dispersion, peptisation and mechanical dispersion not by coagulation.
Gold number is associated with protective colloid.
Tyndall effect is seen in colloidal solution.
Positive charged AgI sol obtained due to adsorption of Ag+ ions on AgI molecules.
Substance added to stabilise the emulsion is known as emulsifier or emulsifying agent.
Lyophilic colloids are extensively soluated. So, are more stable.
Mist— dispersed phase – liquid.
dispersion medium – Gas.
Fog is an example of aerosols.
dispersed phase – liquid
In emulsion, dispersed medium and dispersed phase both are liquid.
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