Surface chemistry is an important part of Class 12 chemistry, and one of the key topics within this chapter is the study of colloids. Among different types of colloidal systems, lyophilic colloids hold a special place because of their stability and unique properties. Aspirants preparing for board examinations and competitive entrance tests often revise this topic through Lyophilic colloid mcqs class 12 with answers, which help strengthen conceptual understanding and improve problem-solving skills. Practicing Lyophilic colloid mcqs class 12 with answers allows aspirants to revise the fundamental properties and behavior of these colloidal systems effectively.

Lyophilic colloids are colloidal solutions in which the dispersed phase has a strong affinity for the dispersion medium. The term “lyophilic” literally means “solvent-loving.” In aqueous solutions, these colloids are sometimes referred to as hydrophilic colloids. Common examples include starch, gelatin, gum, and proteins. These substances interact strongly with the solvent, forming highly stable colloidal systems. Many conceptual questions about these properties appear in Lyophilic colloid mcqs class 12 with answers, making them useful for thorough revision. By studying Lyophilic colloid mcqs class 12 with answers, students can better understand why lyophilic colloids behave differently from lyophobic colloids.

One of the most important characteristics of lyophilic colloids is their stability. The particles in these systems are surrounded by a layer of solvent molecules, which prevents them from aggregating and settling down. This process is known as solvation or hydration. Because of this protective layer, lyophilic colloids are highly stable and do not easily coagulate. Many exam questions test this property, which is why students frequently practice Lyophilic colloid mcqs class 12 with answers to understand the stability of these systems. Reviewing Lyophilic colloid mcqs class 12 with answers also helps aspirants remember that these colloids can be easily regenerated if precipitated.

Another important feature of lyophilic colloids is their reversible nature. If the dispersion medium is removed, the colloidal particles may precipitate, but they can be redispersed simply by adding the solvent again. This reversibility distinguishes them from lyophobic colloids, which often form irreversible precipitates. Questions comparing reversible and irreversible colloids commonly appear in Lyophilic colloid mcqs class 12 with answers, helping aspirants clearly differentiate between the two types. Practicing Lyophilic colloid mcqs class 12 with answers makes it easier to recall these distinctions during examinations.

Lyophilic colloids also exhibit higher viscosity compared to the pure dispersion medium. The interaction between the dispersed particles and the solvent molecules increases resistance to flow. This property is frequently mentioned in theoretical questions and explanations within Lyophilic colloid mcqs class 12 with answers. When students practice Lyophilic colloid mcqs class 12 with answers, they become familiar with how viscosity changes in colloidal systems and why lyophilic sols behave differently from true solutions.

Another concept related to lyophilic colloids is their protective action. Lyophilic sols can protect lyophobic sols from coagulation when electrolytes are added. This phenomenon is called protective colloidal action. The effectiveness of a protective colloid is measured using the gold number, which indicates the minimum amount of protective colloid needed to prevent coagulation. Such concepts are frequently included in Lyophilic colloid mcqs class 12 with answers, allowing aspirants to understand both theoretical and practical aspects of colloidal chemistry. Studying Lyophilic colloid mcqs class 12 with answers helps reinforce how protective colloids function in stabilizing colloidal dispersions.

Lyophilic colloids also play an important role in biological and industrial processes. Many biological fluids, including blood plasma and cytoplasm, behave like colloidal systems. Similarly, industrial products such as paints, inks, and food emulsions rely on colloidal stability. Understanding the properties of lyophilic colloids therefore has both scientific and practical significance. These applications are often discussed in Lyophilic colloid mcqs class 12 with answers, helping students relate textbook knowledge to real-world examples. By reviewing Lyophilic colloid mcqs class 12 with answers, aspirants gain a broader understanding of how colloids function in everyday life.

Another important feature of lyophilic colloids is their ability to form sols through simple mixing. Unlike lyophobic sols, which often require special preparation methods, lyophilic sols can be prepared by directly dissolving the substance in the solvent. This ease of preparation is frequently highlighted in Lyophilic colloid mcqs class 12 with answers, making it an important point for aspirants to remember. Practicing Lyophilic colloid mcqs class 12 with answers ensures that aspirants understand how preparation methods differ among various colloidal systems.

Lyophilic Colloid MCQqs Class 12 with Answers:

Q1.

The process in which colloids move towards an electrode when subjected to a DC electric field is called:

A. Brownian movement
B. Tyndall effect
C. Peptization
D. Electrophoresis

Answer: D

Q2.

Which of the following does not show the Tyndall effect?

A. Cloud
B. Milk
C. Sugar solution
D. Suspension

Answer: C

Q3.

The colloidal solution used to treat stomach disorders is:

A. Silver sol
B. Antimony sol
C. Milk of magnesia
D. Gold sol

Answer: C

Q4.

Assertion: Colloidal particles pass through ordinary filter paper.
Reason: Ultrafiltration is a slow process.

A. Both A and R are correct and R explains A
B. Both A and R are correct but R is not the explanation
C. A is correct but R is incorrect
D. A is incorrect but R is correct

Answer: B

Q5.

Which methods are used for coagulation of lyophobic colloids?

I. Cooling
II. Electrophoresis
III. Mixing oppositely charged sols
IV. Dialysis for short duration

A. I, II
B. II, III
C. I, II, IV
D. II, IV

Answer: B

Q6.

Smoke is an example of:

A. Sol
B. Aerosol
C. Foam
D. Solid sol

Answer: B

Q7.

Compared to true solutions, colloidal solutions show:

A. Lower osmotic pressure
B. Higher freezing point depression
C. Higher boiling point elevation
D. Higher vapor pressure

Answer: A

Q8.

Which condition favors faster Brownian movement?

A. Smaller size and higher viscosity
B. Smaller size and lower viscosity
C. Larger size and higher viscosity
D. Larger size and lower viscosity

Answer: B

Q9.

When highly diluted AgNO₃ is added to highly diluted KI solution, the sol formed is:

A. AgI/NO₃⁻
B. AgI/Ag⁺
C. AgI/K⁺
D. AgI/I⁻

Answer: B

Q10.

In which colloid both lyophilic and lyophobic parts are present?

A. Micelle
B. Gold sol
C. Rubber sol
D. As₂S₃ sol

Answer: B

Q11.

Which statement is incorrect regarding colloidal solutions?

A. Shows colligative properties
B. Shows Brownian motion
C. Flocculating power of Al³⁺ > Na⁺
D. Filter paper stops colloidal particles

Answer: D

Q12.

Which are hydrophobic sols?

i. Protein
ii. Gold
iii. Gum
iv. Fe(OH)₃

A. i, iii
B. ii, iii
C. i, iv
D. ii, iv

Answer: D

Q13.

When FeCl₃ is added to excess hot water, the colloidal particles formed have:

A. Positive charge
B. Sometimes positive, sometimes negative
C. Neutral charge
D. Negative charge

Answer: A

Q14.

Which statement is false for hydrophilic sols?

A. Do not require electrolytes for stability
B. Reversible in nature
C. Viscosity same as water
D. Cannot be easily coagulated

Answer: C

Q15.

Charges on CdS sol and TiO₂ sol respectively are:

A. Positive, positive
B. Positive, negative
C. Negative, negative
D. Negative, positive

Answer: D

Q16.

Lyophilic sols are more stable than lyophobic sols because:

A. Strong electrostatic repulsion
B. Particles positively charged
C. Particles have no charge
D. Particles are solvated

Answer: D

Q17.

Tyndall effect is shown most effectively by:

A. True solution
B. Lyophilic colloid
C. Lyophobic colloid
D. Suspension

Answer: C

Q18.

Which sol contains negatively charged particles?

A. FeCl₃ + hot water
B. KI added to AgNO₃
C. AgNO₃ added to KI
D. Al₂(SO₄)₃ in water

Answer: C

Q19.

Correct matching:

Cheese → Dispersion of liquid in solid
Pumice stone → Dispersion of gas in solid
Hair cream → Dispersion of liquid in liquid
Cloud → Dispersion of liquid in gas

Correct option:

A. A–IV, B–III, C–II, D–I
B. A–IV, B–I, C–III, D–II
C. A–III, B–IV, C–I, D–II
D. A–IV, B–III, C–I, D–II

Answer: D

Q20.

Protective power of a lyophilic colloid is expressed by:

A. Critical micelle concentration
B. Standard reduction potential
C. Gold number
D. Oxidation number

Answer: C

Q21.

Lyophilic sols are stable because:

A. Particles not solvated
B. Strong electrostatic interaction
C. No charge on particles
D. Brownian

Answer:B

Q22.

Tyndall effect is observed when:

A. Diameter of dispersed particles is much larger than wavelength of light
B. Diameter of dispersed particles is much smaller than wavelength of light
C. Refractive index of dispersed phase is greater than dispersion medium
D. Diameter of dispersed particles is similar to the wavelength of light

Answer: D

Q23.

A sample of red ink (a colloidal suspension) is prepared by mixing eosin dye, egg white, formaldehyde (HCHO), and water. The component which ensures stability of the ink sample is:

A. Egg white
B. Eosin dye
C. HCHO
D. Water

Answer: A

Q24.

Which of the following methods is used for the preparation of colloids?

A. Bredig’s arc method
B. Ostwald process
C. Mond process
D. Van Arkel method

Answer: A

Q25.

Which property is characteristic of Lyophilic colloids?

A. Irreversible nature
B. Low stability
C. High viscosity compared to the dispersion medium
D. Easy Coagulation

Answer: C

Q26.

Krafft temperature is the temperature:

A. Below which detergent solutions start freezing
B. Below which micelles start forming
C. Above which detergents start boiling
D. Above which micelles start forming

Answer: D

Q27.

Measurement of zeta potential helps determine:

A. Viscosity
B. Solubility
C. Stability of colloidal particles
D. Size of colloidal particles

Answer: C

Q28.

The charge on colloidal particles is mainly due to:

A. Presence of electrolyte
B. Very small particle size
C. Adsorption of ions from solution
D. Cannot be determined

Answer: C

Q29.

Which statement is incorrect regarding surface tension?

1. Liquids tend to have minimum surface area due to surface tension

2. Surface tension decreases with increase in temperature

3. SI unit of surface tension is N m⁻¹

4. Surface tension is smaller when intermolecular forces are stronger

A. 1
B. 2
C. 3
D. 4

Answer: D

Q30.

An example of a hydrophobic sol among the following is:

A. Gum solution
B. Arsenic sulphide solution
C. Starch solution
D. Protein solution

Answer: B

In conclusion, lyophilic colloids are an essential topic in Class 12 surface chemistry because they illustrate how molecular interactions influence the behavior of colloidal systems. Their stability, reversibility, viscosity, and protective action make them unique among colloidal solutions. For aspirants preparing for exams, revising these concepts through Lyophilic colloid mcqs class 12 with answers is highly beneficial. Continuous practice of Lyophilic colloid mcqs class 12 with answers helps build strong conceptual clarity and ensures better performance in board examinations and competitive entrance tests.