Surface Chemistry (Old NCERT) - Free MCQ Practice Test with solutions,

A gas with high critical temperature has high vander waal force due to which they are more easily liquefiable & hence more easily adsorb as adsorption decreases  their energy

Extent of adsorption increase with increase in critical temperature

Extent of adsorption & intermoleculer force ∞ vander waal const. (a) NH₃ > CO₂ > CH₄

Refer theory

Milk is emulsion

H₂O + SiO₂ → SiO₂. xH₂O
Sillica gel

Emulsion :- (ℓ + ℓ) dispersed phase & dispersion medium both are liquid

Gelation, starch & gum are organic in nature & hence lyophilic in nature but S₈ is inorganic in nature & hence lyophobic in nature

Vander waal force is responsible for adsorption.

Tyndall effect is due to scattering of light

Chemisorption is irreversible in nature because in chemisorption there are strong covalent bond are formed which do not brake easily to separate the reactants because of this it has high heat of adsorption, takes place at high temperatures and forms monolayers.

Colloidal range of particle is 1nm-1000 nm

colloids are heterogeneous in nature & hence consist of two phase.

Refer theory

Milk is emulsion (butter fat dispersed in water).

The correct answer is option  D

Stability of the lyophobic sols is due to presence of charge on colloidal particles. If charge is removed, particles come together and settle down. Spontaneous destabilization of solution is ageing and destabilization of solution by artificial means is called coagulation.
Methods of coagulation are as follows:
1. Boiling
2. Dialysis
3. Addition of electrolytes
4. Mixing two oppositely charged sols
5. Electrophoresis

Fog (liquid + gas) dispersed phase Dispersion medium.

As per Hardy shulze rule coagulation power a +ve charge which is maximum in Al³⁺.

Ultra–microscope is based on tyndall effect which is based on scattering of light.

Molecular size for colloidal range in 1nm–1000 nm.

Refer theory

Due to charge on colloidal particle they move under the influence of electric field.

Neutralization of charge on colloid as per hardy shulze rule.

Lyophilic colloids do not move in presence of electric field due to uncharged nature.

As₂S₃ colloid can be represented as As₂S₃ s^2–
so it is negatively charged.

Crystalloid & colloids differes in particle size & due to smaller size of crystalloid.

Micelle is a associated form of colloid

Alums due to the charged nature of colloidal particle & hence coagular impurities in muddy water as per shulze rule.

Ethanol is alcohol to the colloidal system is called alcosols.

Colloidal sols formed by mixing substances in a suitable dispersion medium are called lyophilic sols. These are quite stable. They are also known as reversible sols because the dispersion medium can be separated from the colloid by means of physical methods like evaporation. For e.g. gum, gelatin, starch, rubber etc.