Test: Properties Of Colloids


20 Questions MCQ Test Chemistry Class 12 | Test: Properties Of Colloids


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This mock test of Test: Properties Of Colloids for Class 12 helps you for every Class 12 entrance exam. This contains 20 Multiple Choice Questions for Class 12 Test: Properties Of Colloids (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Properties Of Colloids quiz give you a good mix of easy questions and tough questions. Class 12 students definitely take this Test: Properties Of Colloids exercise for a better result in the exam. You can find other Test: Properties Of Colloids extra questions, long questions & short questions for Class 12 on EduRev as well by searching above.
QUESTION: 1

When colloids are subjected to an electrical field particles move towards an electrode and precipitate. Name the process.

Solution:

The correct answer is Option B.

It is the migration of electrically charged colloidal particles in one direction under the influence of an electric field. When colloidal particles move towards a positive electrode, they are negatively charged and vice versa. Electrophoresis is used to measure the rate of migration of sol particles

QUESTION: 2

Which property is represented by the following figure;

Solution:

The correct answer is Option C.
The random movement of microscopic particles suspended in a liquid or gas, caused by collisions between these particles and the molecules of the liquid or gas in free space is called Brownian movement.

QUESTION: 3

Which law is represented by the following expression?

For a positive colloid the order of precipitation is : Phosphate ion>sulphate ion >chloride ion.

Solution:

The correct answer is option C.
1. Minimum quantity of an electrolyte required to cause precipitation of a sol is called its coagulating value.
2. Greater the charge on flocculating ions and smaller is the amount of electrolyte required for precipitation, higher is the coagulating power of coagulating ions (Hardy Schulze Law).
3. Phosphate ion bears −3 charge, sulphate ion bears -2 charge and chloride ion carries only −1 charge and due to high charge the coagulating power of phosphate is higher than chloride.
 

QUESTION: 4

Which substance is added to water containing suspended impurities to coagulate the suspended impurities and make water fit for drinking purposes.

Solution:

The correct answer is Option D
 When alum is added to raw water it reacts with the bicarbonates alkalinities present in water and forms a gelatinous precipitate.
It neutralizes all the suspended impurities of water resulting in their coagulation.

QUESTION: 5

The simplest way to check whether a system is a colloid is by using:

Solution:

The Tyndall Effect is the effect of light scattering in colloidal dispersion, while showing no light in a true solution. This effect is used to determine whether a mixture is a true solution or a colloid.

QUESTION: 6

Which method cannot be used for the coagulation of the lyophobic sol?

Solution:

Coagulation is the destabilization of Colloids by neutralizing the electric charge of the dispersed phase particles, which results in aggregation of the colloidal particles.

 

QUESTION: 7

Lyophilic colloids that shows the property of protecting lyophobic colloids are also called as:

Solution:

Lyophilic colloids have a unique property of protecting lyophobic colloids. When a lyophilic sol is added to the lyophobic sol, the lyophilic particles form a layer around lyophobic particles and thus protect the latter from electrolytes. Lyophilic colloids use for this purpose are called protective colloids.

QUESTION: 8

Which of the following forms a colloidal solution in water?

Solution:

The substance which forms the colloidal solution in water is starch. A colloidal solution is a solution in which the colloid mixes uniformly. All colloids have a Tyndall Effect, which is not exhibited by glucose. Starch is a colloid and thus when mixed with water can form the colloidal solution.

QUESTION: 9

The factors which are responsible for the stability of lyophilic sols are:

Solution:
QUESTION: 10

The Brownian motion is due to:

Solution:
QUESTION: 11

Which property of colloids is applied in rubber plating & sewage disposal?

Solution:

The correct answer is Option D.
Electrophoresis movement of colloidal particles towards an electrode, when they are subjected to an electrical field.

QUESTION: 12

In Tyndall effect the colloidally suspended particles:

Solution:

The correct answer is option A
In Tyndall effect the colloidally suspended particles trace out the path of the strong beam of light because of scattering of light by the colloidal particles.
 

QUESTION: 13

Ferric hydroxide is a negative sol, which of the following electrolyte will coagulate it most:​

Solution:

If FeCl3 is added to excess of hot water, a positively charged sol of hydrated ferric oxide is formed due to adsorption of Fe3+ ions.
Ferric hydroxide is a negative sol,FeCl3 electrolyte will coagulate the most.

QUESTION: 14

What is aggregation of colloidal particles into insoluble precipitate by addition of some suitable electrolyte called?

Solution:

Aggregation of colloidal particles into insoluble precipitate by addition of some suitable electrolyte is called coagulation.

QUESTION: 15

A fresh precipitate can be transformed into colloidal sol by:

Solution:

The dispersion of a freshly precipitated material into colloidal solution by the action of an electrolyte in solution is termed peptization. The electrolyte used is called a peptizing agent. For Example, sols obtained by peptization are: Freshly prepared ferric hydroxide on treatment with a small amount of ferric chloride solution at once forms a dark reddish brown solution. Ferric chloride acts as a peptizing agent.

QUESTION: 16

Which statement describes coagulation value?

Solution:

The correct answer is option D
The coagulation of a colloidal solution by an electrolyte does not take place until the added electrolyte has certain minimum concentration in the solution. The minimum concentration of an electrolyte in millimoles per litre required to cause precipitation of a sol in two hours is called coagulating value. The smaller the quantity needed, the higher will be the coagulating power of an ion.

QUESTION: 17

Which electrolyte will precipitate a negatively charged colloids (As2S3 sol) to a greater extend?​

Solution:

The correct answer is Option D
Fe3+
Coagulation power is directly proportional to the magnitude of charge on the ion.
 

QUESTION: 18

The process in which colloid is placed inside a bag of semi permeable membrane like cellophane or parchment paper which permits ions and not colloids to pass through, is called as:

Solution:

Dialysis is a process in which colloid is placed inside a bag made of semi permeable membrane like cellophane or parchment paper which permits ions and not colloids to pass through.

QUESTION: 19

Which of the following will have the highest coagulating power for As2S3 colloids?

Solution:

The correct answer is Option A.

AS2S3 is an anionic sol (negative sol) hence coagulation will depend on coagulating power of cation , which is directly proportional to the valency of the cation (Hardy-Schulze rule). 
Hence positive ions having maximum amount of charge will have more coagulation thus, Al3+ have maximum coagulating power.

QUESTION: 20

What is scattering of light by mist on head light of vehicles called?

Solution:

The correct answer is Option D
Tyndal effect is scattering of light when a ray of light is passed through a colloidal solution made forming a tyndall cone.