All questions of Surface Chemistry for JEE Exam

Healthy kidneys clean your blood and remove extra fluid in the form of urine. They also make substances that keep your body healthy. Dialysis replaces some of these functions when your kidneys no longer work.

Cake batter an emulsion ,cheese a gel ,solid in liquid malai,milk emulsion, so marble is left

The ultracentrifuge is a centrifuge optimized for spinning a rotor at very high speeds, capable of generating acceleration as high as 1 000 000 g (approx. 9 800 km/s2). There are two kinds of ultracentrifuges, the preparative and the analytical ultracentrifuge.

AgCl beinga covalent molecule is insoluble in water and hence hydrophobic.

Above this concentration only the surfactants form micelles and micelle formation takes place. To reach this concentration, a temperature is required which is called Critical Micelle temperature or Kraft temperature

The actual dispersed liquid is a colloid of which there are many examples. Any colloid consisting of a solid dispersed in a gas is called a smoke. A liquid dispersed in a gas is referred to as a fog. So it appears that fog is an example of a colloid of tiny particles of water vapor and air.

Hydrophilic colloids: These are water-loving colloids. The colloid particles are attracted to the water. They are also known as reversible sols. Examples include Agar, gelatin, pectin, etc

Hydrophobic colloids: These are the opposite in nature to hydrophilic colloids. The colloid particles are repelled by water. They are also called irreversible sols. Examples include Gold sols, clay particles, etc
therefore than can easily form supersaturated solution

Colloids can be purified by 3 methods mainly-- dialysis, electrodialysis and ultrafiltration.

There are many answers based upon different reasoning but if there would be a direct answer then it would have been like
AT CMC micelle formation takes place...
option a ,b ,d does not say about the formation of micelle but option c says associativity which means formation of micelle.... thus it can be your direct answer.

>b)CO2 >NH3

This is because the adsorption of gases on charcoal is dependent on the size and shape of the gas molecule, as well as the nature of the charcoal surface. In general, smaller molecules are more easily adsorbed than larger ones, and polar molecules are more easily adsorbed than nonpolar ones.

NH3 is a polar molecule, but it is larger than CO2 and CH4, so it is less easily adsorbed. CO2 is a small nonpolar molecule, so it is more easily adsorbed than NH3 but less easily adsorbed than CH4. CH4 is the smallest and most nonpolar of the three gases, so it is the most easily adsorbed.

Therefore, the correct order of gas adsorption is CH4 > CO2 > NH3.

I think it's a misprint.. it must be cmc-critical micelles concentration and at cmc molecules associate., formation of aggregates

Both the statements are correct. this is hardy schulze rule given in ncert chemistry surface chemistry

Brownian Movement:

• Brownian movement is the random movement of particles suspended in a fluid due to collisions with molecules of the surrounding medium.

• The magnitude of Brownian movement is directly proportional to the size of the particle.

• Hence, the smaller the particle, the more pronounced is the Brownian movement.

Sols of Metal Sulphides:

• A sol is a colloidal solution in which the dispersed phase is a solid and the dispersion medium is a liquid.

• Lyophilic sols are those in which the dispersed phase has a strong affinity for the dispersion medium.

• Metal sulphides are usually lyophobic, i.e., they have a weak affinity for the dispersion medium.

• Hence, option 'B' is incorrect.

Schulze-Hardy Law:

• Schulze-Hardy law states that the greater the size of the ion, the greater is its coagulating power.

• Coagulation is the process of settling down of colloidal particles under the influence of some external agency.

• The law holds good for ions of the same charge and for the same concentration of the electrolyte.

• Hence, option 'C' is incorrect.

Adsorption:

• Adsorption is the process of accumulation of a substance at the surface of a solid or a liquid.

• The strength of adsorption depends on the nature of the adsorbent and the adsorbate.

• Charcoal is a good adsorbent for many substances, including chlorine and hydrogen sulphide.

• However, the strength of adsorption depends on the nature of the adsorbate.

• Hence, option 'D' is incorrect.

Conclusion:

• Option 'A' is correct as the Brownian movement is more pronounced for smaller particles than for bigger ones.

Lyophilic sols are also known as reversible sols because they can be prepared by simply mixing the dispersed phase with the dispersion medium without any chemical reaction. Here, we will discuss the given statement and why option 'C' is not correct.

Statement Analysis:

a) There is a considerable interaction between the dispersed phase and dispersion medium:
- Lyophilic sols have a strong interaction between the dispersed phase and dispersion medium due to the formation of a solvation layer around each particle.
- The solvation layer is formed due to the adsorption of the solvent molecules on the surface of the dispersed phase.

b) These are quite stable and are not easily coagulated:
- Lyophilic sols are quite stable and can be stored for a longer period of time without any coagulation.
- This stability is due to the strong interaction between the dispersed phase and dispersion medium.

c) They carry charge:
- This statement is not correct as lyophilic sols do not carry any charge on their particles.
- They are different from lyophobic sols, which carry a charge due to the adsorption of ions on the surface of the particles.

d) The particles are hydrated:
- Lyophilic sols have a high degree of solvation due to the formation of a solvation layer around each particle.
- This solvation layer contains the solvent molecules that are adsorbed on the surface of the particle.

Conclusion:

- Option 'C' is not correct as lyophilic sols do not carry any charge on their particles.
- Lyophilic sols have a strong interaction between the dispersed phase and dispersion medium, which makes them stable and not easily coagulated.
- The particles in lyophilic sols are hydrated due to the formation of a solvation layer around each particle.

Gold numbers are defined as the minimum amount of protective colloid in milligrams which prevents a colour change from red to violet of 10 ml gold sol by the addition of 1 ml of 10% NaCl solution. More is the gold number, less is the protective power of lyophilic colloid since it means that amount required is more. 

Introduction:
Colloids are a type of mixture that consist of two phases: a dispersed phase and a continuous phase. The dispersed phase consists of small particles or droplets that are dispersed throughout the continuous phase. Colloids are different from solutions because the particles in colloids are larger and do not dissolve completely in the continuous phase.

Explanation:

b) Are two-phase systems:
Colloids are two-phase systems because they consist of two distinct phases - the dispersed phase and the continuous phase. The dispersed phase contains the particles or droplets that are dispersed throughout the continuous phase. The continuous phase is the medium in which the dispersed phase is dispersed. Examples of colloids include milk, mayonnaise, and fog. In milk, for example, fat globules are dispersed throughout the water-based continuous phase.

a) Are suspensions of one phase in another:
This statement is incorrect. Colloids are not suspensions of one phase in another. Suspensions are heterogeneous mixtures in which solid particles are dispersed in a liquid or gas. In suspensions, the particles are larger and can settle over time. In colloids, the particles are smaller and remain dispersed throughout the continuous phase due to the repulsive forces between them.

c) Contain only water-soluble particles:
This statement is incorrect. Colloids can contain particles that are soluble or insoluble in the continuous phase. For example, in an oil-in-water emulsion, the oil droplets are insoluble in water but are dispersed throughout it. Similarly, in a gelatin colloid, the gelatin particles are soluble in water but form a gel-like structure.

d) Are true solutions:
This statement is incorrect. Colloids are not true solutions. True solutions are homogeneous mixtures in which the solute particles are completely dissolved in the solvent. In colloids, the dispersed phase consists of particles that are larger and do not dissolve completely in the continuous phase. The particles in colloids can be seen under a microscope and can scatter light, giving colloids their characteristic opaqueness or translucence.

Conclusion:
In summary, colloids are two-phase systems consisting of a dispersed phase and a continuous phase. They are not suspensions of one phase in another, do not necessarily contain only water-soluble particles, and are not true solutions. Colloids have unique properties and can be found in various everyday substances.

Mud water contains charged colloidal particles which is neutralized by adding alum

“The minimum concentration of an electrolyte which is required to cause the coagulation or flocculation of a sol is known as flocculation value.” “The number of millimoles of an electrolyte required to bring about the coagulation of one litre of a colloidal solution is called its flocculation value.”

Size of colloidal particles may range from 1 to 1000 nm.

Colloidal particles are particles that are intermediate in size between true solutions and suspensions. They are larger than individual molecules but smaller than visible particles. The size of colloidal particles plays a crucial role in determining their properties and behavior. Let's explore why the correct answer is option 'A' and understand the range of colloidal particle sizes.

Definition of Colloidal Particles:
Colloidal particles are defined as particles that range in size from 1 to 1000 nanometers (nm). These particles are typically composed of clusters of atoms or molecules and are dispersed in a continuous medium, such as a liquid or gas. The size range of colloidal particles is important because it allows them to exhibit unique properties and behavior due to their large surface area-to-volume ratio.

Key Points:
- Colloidal particles range in size from 1 to 1000 nm.
- They are larger than individual molecules but smaller than visible particles.
- Colloidal particles are composed of clusters of atoms or molecules.
- They are dispersed in a continuous medium, such as a liquid or gas.
- The size range of colloidal particles allows them to exhibit unique properties.

Importance of Colloidal Particle Size:
The size of colloidal particles is crucial as it directly impacts their stability, optical properties, and reactivity. The small size of colloidal particles gives them a large surface area, which leads to increased interactions with their surrounding medium and enhanced reactivity. Additionally, the size of colloidal particles affects their ability to scatter light, making them useful in various applications such as inks, paints, and pharmaceutical formulations.

Applications of Colloidal Particles:
Colloidal particles find applications in various fields due to their unique properties. Some common applications include:

1. Medicine and Healthcare: Colloidal particles are used in drug delivery systems, where the small size allows for easy absorption and targeted delivery of medications.

2. Food Industry: Colloidal particles are used as stabilizers, emulsifiers, and thickeners in food products to improve texture and stability.

3. Environmental Remediation: Colloidal particles can be used to remove pollutants from water and soil through processes such as adsorption and coagulation.

4. Nanotechnology: Colloidal particles are used as building blocks for the fabrication of nanomaterials with tailored properties.

In conclusion, the correct answer to the question is option 'A' as the size of colloidal particles typically ranges from 1 to 1000 nm. The size range is significant in determining the unique properties and applications of colloidal particles in various fields.