How non-polar and polar part in micelle are arranged ?

Polar at outer surface and non-polar at inner surface
Polar at inner surface and non-polar at outer surface
Both polar and non-polar at inner surface
Distributed all over the surface

Solution

Pure water can be obtained from sea water by

Centrifugation
Plasmolysis
Reverse osmosis
Sedimentation

Solution

The osmotic pressure of sea water is 25 atm at 15°C.When pressure greater than 26 atm is applied on seawater separated by a rigid emipermeable membrane,pure water is obtained.

Colloidal solutions are not purified by

Dialysis
Electrodialysis
Ultrafiltration
Electrophoresis

Solution

Colloidal solutions are not purified by electrophoresis.Movement of colloidal particles under the influence of electric field is called electrophoresis. So, it can make easier. Electrophores is is the property of colloids not the purification method.

Which of the following methods is used for the destruction of sol ?

Condensation
Dialysis
Diffusion through animal membrane
Addition of an electrolyte.

Solution

Addition of electrolytes causes precipitation(coagulation)of a sol.

Which of the following is used for neutralising charge on colloidal solution?

Electrons
Electrolytes
Positively charged ions
Compounds

Solution

Electrolytes are used for neutralising charge on colloidal particles.

Hardy-Schulze rule explains the effect of electrolytes on the coagulation of colloidal solution. According to this rule,coagulation power of cations follow the order

Ba⁺² > Na⁺ > Al⁺³
Al⁺³ > Na⁺ > Ba⁺²
Al⁺³ > Ba⁺² > Na⁺
Ba⁺² > Al⁺³ > Na⁺

Solution

According to this law the coagulating effect of anion on dispersed phase of opposite charge increases with the increase in valency of the ion. The precipitating power of Al³⁺, Ba⁺⁺, Na⁺ ions is in order Al³⁺ > Ba²⁺ > Na⁺.

The colloidal solution of gelatin is known as

Solvent loving sol
Reversible sol
Hydrophilic sol
All the above

Solution

Gelatin is a lyophilic solution (lyo-liquid philic -love).Lyophilic colloids are also known as reversible colloids since on evaporating the dispersion medium (i.e. water),the residue can again be easily reconverted into colloidal state simply by addition of the liquid i.e. water.

At the critical micelle concentration (CMC) the surfactant molecules

decompose
dissociate
associate
become completely soluble

Solution

The critical micelle concentration is the lowest concentration at which micelle formation appears when surfactants are present above that CMC, they can act as emulsifiers that will solubilise a compound which is normally insoluble in the solvent being used.

During dialysis

only solvent molecules can diffuse
solvent molecules, ions and colloidal particles can diffuse
all kinds of particles can diffuse through the semi-permeable membrane
solvent molecules and ions can diffuse

Solution

The use of membrane for separating colloidal particles from those of crystalloids is termed as dialysis. Hence it is clear that colloidal particles cannot pass through animal parchment membrane. Hence only solvent molecules and ions (in case of electrodialysis) can diffuse through membrane

Which one of the following substances gives a positive charged sol?

Gold
A metal sulphide
Ferric hydroxide
An acidic dye

Solution

Fe(OH)₃ particles absorb Fe³⁺ ions and get peptized to give a positively charged sol

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