Chemistry 1 Marks Question

Foam ; e.g. froth, whipped cream, soap lather.

Dispersed phase: liquid, Dispersion medium: liquid/ liquid fat dispersed in water.

Like charged particles cause repulsion/Brownian movement/solvation.

Sol : example- paints, cell fluids

In adsorption there is development of inter particle attractions between adsorbate & adsorbent.

Gel e.g. cheese, butter, jellies.

It first increases then decreases or graphical representation.

Chemisorption.

The catalytic reaction in which the pore structure of the catalyst and the size of the reactant and product molecules are comparable.

The process of settling of colloidal particles is called coagulation.

Chemisorption.

To make the surface available again for more reaction to occur/To remove the product formed from the surface of the catalyst.

Like Charged particles cause repulsion/Brownian motion/solvation.

Sol – paint, cell fluids.
Gel – cheese, butter, jellies.

Both are surface phenomenon/ both increase with increase in surface area.

The movement of colloidal particles under an applied electric potential towards oppositely charged electrodes is called electrophoresis.

Emulsions are liquid-liquid colloidal systems.

The scattering of light by colloidal particles is called “Tyndall effect”.

Due to unbalanced bombardment of the colloidal particles by the molecules of the dispersion medium.

• Emulsion: It is a colloidal mixture in which both the dispersed phase and the dispersion medium are liquids. The two or more liquids present in the mixture are generally immiscible in nature.

Example: Milk.

• Gel: It is a colloid in which the dispersed phase i.e. liquid has combined with the dispersion medium i.e. solid to produce a semisolid material.

Example: jellies.

Due to formation of n-type semiconductor providing free electrons.

Some medicines are more effective in colloidal form because medicine in colloidal form is easily absorbed by the body tissues.
For example: Antibiotics like streptomycin in the form of the colloidal sol is injected into the body for the more effective result.

When a beam of light is passed through a colloidal solution, then scattering of light is observed. This is known as the Tyndall effect. This scattering of light illuminates the path of the beam in the colloidal solution.

Dialysis is based on the principle that ions can pass through semipermeable membrane whereas colloidal particles cannot pass through it.

If the adsorbate is held on an adsorbent surface by weak van der Waal's forces, the adsorption is called physical adsorption.

Colloids can be classified on various bases:
On the basis of the physical state of the components (by components we mean the dispersed phase and dispersion medium). Depending on whether the components are solids, liquids, or gases, we can have eight types of colloids.

Zeolites are alumino-silicates that are micro-porous in nature. Zeolites have a honeycomb-like structure, which makes them shape-selective catalysts. They have an extended 3D-network of silicates in which some silicon atoms are replaced by aluminium atoms, giving them an Al−O−Si framework. The reactions taking place in zeolites are very sensitive to the pores and cavity size of the zeolites. Zeolites are commonly used in the petrochemical industry.

Catalysts provide an alternate path involving lower activation energy for the reactants.

Medicines are more effective in the colloidal form because of large surface area and are easily assimilated in this form.

The process of removing a dissolved substance from a colloidal solution by the means of diffusion through a membrane is known as dialysis. This process is based on the principle that ions and small molecules can pass through animal membranes unlike colloidal particles.

1. Chemisorption is highly specific in nature. It occurs only if there is a possibility of chemical bonding between the adsorbent and the adsorbate.
2. Like physisorption, chemisorption also increases with an increase in the surface area of the adsorbent.

When a beam of light is allowed to pass through a colloidal solution, it becomes visible like a column of light. This is known as the Tyndall effect. This phenomenon takes place as particles of colloidal dimensions scatter light in all directions.

This can be done:

1. By adding an electrolyte.
2. By adding a suitable solvent.

Blood is a colloidal solution when we rub moist alum on that part it causes coagulation which stops bleeding.

A colloidal solution having alcohol as the dispersion medium and a solid substance as the dispersed phase is called an alcosol.
For example: colloidal sol of cellulose nitrate in ethyl alcohol is an alcosol.

Colloidal system in which solid is dispersed in liquid is called sol and that in which liquid is dispersed in solid is called gel.

Clouds are colloidal in nature and carry charge. Spray of silver iodide, an electrolyte, results in coagulation leading to rain.

Colloids can be classified on various bases:
On the basis of the dispersion medium, sols can be divided as:

Dispersion medium	Name of sol
Water	Aquasol or hydrosol
Alcohol	Alcohol
Benzene	Benzosol
Gases	Aerosol

A colloidal solution is a state in which the particle size lies between 1nm and 1000nm. It appears to be homogeneous but actually it is heterogeneous.

The colloidal particles are charged and carry either a positive or negative charge. The dispersion medium carries an equal and opposite charge. This makes the whole system neutral. Under the influence of an electric current, the colloidal particles move towards the oppositely charged electrode. When they come in contact with the electrode, they lose their charge and coagulate.

Ne has higher critical temperature, i.e., stronger van der Waals forces therefore easily adsorbed.

1. Sols are dispersions of solids in liquids while emulsions are dispersions of liquids in liquids.
2. Sols are quite stable whereas emulsions are less stable.