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Boost Your Concepts Fast with Challenging Hydrophobic Sol MCQs Class 12 Chemistry

Hydrophobic colloids are an essential topic in the Class 12 surface chemistry chapter, especially for aspirants preparing for board exams and competitive entrance tests. These colloids, also known as lyophobic sols, have very little affinity between the dispersed phase and the dispersion medium. Because of this weak interaction, they require special methods for preparation and stabilization. To understand this topic thoroughly, many aspirants rely on Hydrophobic sol MCQs class 12 chemistry as a key revision strategy. Practicing Hydrophobic sol MCQs class 12 chemistry helps in mastering both conceptual and application-based questions.

Hydrophobic sols include systems such as gold sol, sulphur sol, and arsenic sulphide sol. Unlike lyophilic sols, these colloids are not formed by simple mixing and require specific preparation methods like dispersion or condensation techniques. This difference is frequently tested in exams, which is why aspirants often revise using Hydrophobic sol MCQs class 12 chemistry. By going through Hydrophobic sol MCQs class 12 chemistry, aspirants can easily identify how preparation methods vary between different types of colloids.

One of the most important properties of hydrophobic sols is their instability. Since there is very little attraction between the dispersed particles and the medium, these colloids are easily coagulated by adding small amounts of electrolytes. The ions from the electrolyte neutralize the charge on colloidal particles, causing them to aggregate and precipitate. This concept is central to many questions in Hydrophobic sol MCQs class 12 chemistry, making it crucial for exam preparation. Practicing Hydrophobic sol MCQs class 12 chemistry helps aspirants understand the mechanism of coagulation and the role of electrolytes.

Another key feature of hydrophobic sols is the presence of charge on their particles. The stability of these sols depends on the repulsion between similarly charged particles. This charge is usually acquired by adsorption of ions from the dispersion medium. Techniques such as electrophoresis are used to demonstrate the movement of these charged particles under an electric field. Such topics are frequently covered in Hydrophobic sol MCQs class 12 chemistry, allowing aspirants to build a strong understanding of charge-related phenomena. By solving Hydrophobic sol MCQs class 12 chemistry, aspirants become confident in identifying how charge influences colloidal stability.

The Hardy-Schulze rule is another important concept related to hydrophobic sols. It states that the coagulating power of an electrolyte depends on the valency of the ion carrying a charge opposite to that of the colloidal particles. Higher the valency, greater is the coagulating power. This rule is commonly tested in competitive exams, and aspirants often revise it through Hydrophobic sol MCQs class 12 chemistry. Repeated practice of Hydrophobic sol MCQs class 12 chemistry helps in remembering the correct order of coagulating power among different ions.

Hydrophobic sols also exhibit phenomena such as the Tyndall effect and Brownian movement. The Tyndall effect refers to the scattering of light by colloidal particles, which makes the path of light visible. Brownian movement is the random motion of colloidal particles due to collisions with molecules of the dispersion medium. These phenomena help in identifying colloidal systems and are frequently included in Hydrophobic sol MCQs class 12 chemistry. By practicing Hydrophobic sol MCQs class 12 chemistry, aspirants can clearly understand the physical behavior of these systems.

Another important aspect of hydrophobic sols is their preparation methods. Dispersion methods involve breaking larger particles into colloidal size using techniques such as mechanical dispersion or Bredig’s arc method. Condensation methods involve chemical reactions that lead to the formation of colloidal particles from smaller molecules. Questions related to these methods are commonly seen in Hydrophobic sol MCQs class 12 chemistry, making them important for revision. Students who regularly practice Hydrophobic sol MCQs class 12 chemistry gain clarity on how different methods are applied.

Hydrophobic sols also have several practical applications. They are used in medicine, water purification, and industrial processes. For example, colloidal silver is used for its antibacterial properties, while coagulation is used in water treatment to remove impurities. These applications are often included in Hydrophobic sol MCQs class 12 chemistry, helping aspirants connect theory with real-life uses. Reviewing Hydrophobic sol MCQs class 12 chemistry ensures that aspirants are prepared for both theoretical and application-based questions.

Hydrophobic Sol MCQs Class 12 Chemistry:

Q1.

An example of solid sol is:

A. Gem stones
B. Hair cream
C. Butter
D. Paint

Answer: A

Q2.

Among cheese (C), milk (M), and smoke (S), the correct dispersed phase and dispersion medium respectively is:

A. C: liquid in solid, M: liquid in liquid, S: solid in gas
B. C: solid in liquid, M: liquid in liquid, S: gas in solid
C. C: liquid in solid, M: liquid in solid, S: solid in gas
D. C: solid in liquid, M: solid in liquid, S: solid in gas

Answer: A

Q3.

Among the following, the false statement is:

A. Tyndall effect distinguishes colloid from true solution
B. Artificial rain can be produced by electrified sand
C. Lyophilic sols can be coagulated by electrolytes
D. Latex contains positively charged rubber particles

Answer: D

Q4.

An aerosol is a colloid in which:

A. Gas dispersed in liquid
B. Gas dispersed in solid
C. Liquid dispersed in water
D. Solid dispersed in gas

Answer: D

Q5.

Which of the following statements is correct?

A. Colloidal medicines have small surface area
B. Brownian motion is faster at high viscosity
C. Alum makes water unfit for drinking
D. Lyophobic colloids can be precipitated by electrophoresis

Answer: D

Q6.

The incorrect statement about colloids is:

A. They scatter light
B. They have high molar mass
C. Their osmotic pressure is higher than true solution at same concentration
D. Particle size range is 1–1000 nm

Answer: C

Q7.

Butter is a colloidal solution of:

A. Solid in solid
B. Liquid in solid
C. Solid in liquid
D. Gas in solid

Answer: B

Q8.

Which mixture forms negatively charged AgI sol?

A. 0.1 M AgNO₃ + 0.1 M KI
B. 1 M AgNO₃ + 1.5 M KI
C. 1 M AgNO₃ + 2 M KI
D. 2 M AgNO₃ + 1.5 M KI

Answer: B

Q9.

Which statement about colloids is incorrect?

A. Lyophobic sols are more stable than lyophilic sols
B. Lyophilic sols protect lyophobic sols
C. Lyophilic colloids dissolve better
D. None of these

Answer: A

Q10.

Which reaction prepares a colloidal sol by double decomposition?

A. As₂O₃ + 3H₂S → As₂S₃ + 3H₂O
B. AuCl₃ + HCHO reaction
C. SO₂ + H₂S reaction
D. FeCl₃ + H₂O reaction

Answer: A

Q11.

Which statement is incorrect?

A. Dialysis stabilizes colloids
B. Excess KI gives negative AgI sol
C. Excess KI gives positive AgI sol
D. Colloidal medicines have high surface area

Answer: C

Q12.

Removal of charge from colloids causes:

A. Peptization
B. Coagulation
C. Dialysis
D. Bredig arc method

Answer: B

Q13.

For water-in-oil (W/O) emulsion, the emulsifying agent added is:

A. Soap
B. Heavy metal
C. Gold
D. None

Answer: A

Q14.

Which electrolyte coagulates gold sol fastest?

A. NaCl
B. MgSO₄
C. K₄Fe(CN)₆
D. Al₂(SO₄)₃

Answer: D

Q15.

During electrophoresis of Fe(OH)₃ sol, particles move towards:

A. Anode
B. Cathode
C. Both electrodes
D. Do not move

Answer: B

Q16.

In coagulation of negative sol, flocculating power order is:

A. Al³⁺ > Ba²⁺ > Na⁺
B. Al³⁺ < Ba²⁺ < Na⁺
C. Ba²⁺ > Al³⁺ > Na⁺
D. Na⁺ > Al³⁺ > Ba²⁺

Answer: A

Q17.

Charge on colloidal particles can be demonstrated using:

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

Answer: C

Q18.

Lyophilic sols are stable because:

A. Particles negatively charged
B. Particles positively charged
C. Particles are solvated
D. None

Answer: C

Q19.

Method used to remove excess solute from colloidal solution:

A. Distillation
B. Crystallization
C. Dialysis
D. Gas chromatography

Answer: C

Q20.

Assertion: Fe(OH)₃ and As₂S₃ sols form precipitate on mixing
Reason: They form a new compound

A. Both correct and explanation correct
B. Both correct but explanation incorrect
C. Assertion correct reason incorrect
D. Both incorrect

Answer: C

Q21.

Assertion: Colloidal particles do not move to electrodes
Reason: They have no charge

A. Both correct
B. Both correct but no explanation
C. Assertion correct reason incorrect
D. Both incorrect

Answer: D

Q22.

Assertion: Gold sol changes color on heating
Reason: Metallic bonding increases

A. Both correct explanation correct
B. Both correct not explanation
C. Assertion correct reason incorrect
D. Both incorrect

Answer: C

Q23.

Assertion: Soap is added in O/W emulsion
Reason: Soap reduces surface tension

A. Both correct explanation correct
B. Both correct not explanation
C. Assertion correct reason incorrect
D. Both incorrect

Answer: A

Q24.

Assertion: Water has higher surface tension than most liquids
Reason: Strong hydrogen bonding

A. Both correct explanation correct
B. Both correct not explanation
C. Assertion correct reason incorrect
D. Both incorrect

Answer: A

Q25.

Bredig’s arc method cannot prepare colloid of:

A. Pt
B. Fe
C. Ag
D. Au

Answer: B

Q26.

Gold sol shows different colors because of:

A. Variable oxidation state
B. Different particle sizes
C. Impurities
D. Different concentration

Answer: B

Q27.

Critical micelle concentration (CMC) is:

A. Concentration where micelle formation starts
B. Concentration where true solution forms
C. 1 mol electrolyte per 1000 g solvent
D. Concentration where ΔH = 0

Answer: A

Q28.

Which impurity cannot be removed by electrodialysis?

A. Sodium chloride
B. Potassium sulphate
C. Urea
D. Calcium chloride

Answer: C

Q29.

Tyndall effect occurs when:

I. Particle size much smaller than wavelength
II. Particle size comparable to wavelength
III. Same refractive index
IV. Different refractive index

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

Answer: B

Q30.

Among Na₂SO₄, CaCl₂, Al₂(SO₄)₃ and NH₄Cl, the most effective coagulating agent for Sb₂S₃ sol is:

A. Na₂SO₄
B. CaCl₂
C. Al₂(SO₄)₃
D. NH₄Cl

Answer: C

hydrophobic sol MCQs class 12 chemistry

Conclusion  on Hydrophobic Sol MCQs Class 12 Chemistry

In conclusion, hydrophobic sols are a crucial part of surface chemistry in Class 12. Their properties, preparation methods, stability, and applications make them an important topic for exams. Understanding concepts like coagulation, charge on particles, and the Hardy-Schulze rule is essential for scoring well. Regular practice through Hydrophobic sol MCQs class 12 chemistry helps aspirants revise effectively and build strong conceptual clarity. By consistently studying Hydrophobic sol MCQs class 12 chemistry, aspirants can improve their accuracy and confidence in solving exam questions.

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