Balbharti Maharashtra State Board 11th Chemistry Textbook Solutions
Chapter 11 Adsorption and Colloids Textbook Exercise Questions and Answers.
1. Choose the correct option.
Question A.
The size of colloidal particles lies between
a. 10-10 m and 10-9 m
b. 10-9 m and 10-6 m
c. 10-6 m and 10-4 m
d. 10-5 m and 10-2 m
Answer:
b. 10-9 m and 10-6 m
Question B.
Gum in water is an example of
a. true solution
b. suspension
c. lyophilic sol
d. lyophobic sol
Answer:
c. lyophilic sol
Question C.
In Haber process of production of ammonia K2O is used as
a. catalyst
b. inhibitor
c. promotor
d. adsorbate
Answer:
c. promotor
Question D.
Fruit Jam is an example of-
a. sol
b. gel
c. emulsion
d. true solution
Answer:
b. gel
2. Answer in one sentence :
Question A.
Name type of adsorption in which van der Waals focres are present.
Answer:
Physical adsorption or physisorption.
Question B.
Name type of adsorption in which compound is formed.
Answer:
Chemical adsoiption or chemisorption.
Question C.
Write an equation for Freundlich adsorption isotherm.
Answer:
Freundlich proposed the following empirical equation for adsorption of a gas on solid.
\(\frac{x}{\mathrm{~m}}\) = k P1/n (n > 1) ……(i)
where,
x = Mass of the gas adsorbed
m = Mass of the adsorbent
\(\frac{x}{\mathrm{~m}}\) = Mass of gas adsorbed per unit mass of adsorbent
P = Equilibrium pressure
k and n are constants which depend on the nature of adsorbate, adsorbent and temperature.
3. Answer the following questions:
Question A.
Define the terms:
a. Inhibition
b. Electrophoresis
c. Catalysis.
Answer:
a. Inhibition:
The phenomenon in which the rate of chemical reaction is reduced by an inhibitor is called inhibition.
b. Electrophoresis:
The movement of colloidal particles under an applied electric potential is called electrophoresis.
c. Catalysis:
The phenomenon of increasing the rate of a chemical reaction with the help of a catalyst is known as catalysis.
Question B.
Define adsorption. Why students can read blackboard written by chalks?
Answer:
Hence, students can read blackboard written by chalks.
Question C.
Write characteristics of adsorption.
Answer:
Following are the characteristics of adsorption:
Question D.
Distinguish between Lyophobic and Lyophilic sols.
Answer:
Lyophobic sols (colloids):
Lyophilic sols (colloids):
Question E.
Identify dispersed phase and dispersion medium in the following colloidal dispersions.
a. milk
b. blood
c. printing ink
d. fog
Answer:
Question F.
Write notes on :
a. Tyndall effect
b. Brownian motion
c. Types of emulsion
d. Hardy-Schulze rule
Answer:
a. Tyndall effect:
i. Tyndall observed that when light passes through true solution, the path of light through it cannot be detected.
ii. However, if the light passes through a colloidal dispersion, the particles scatter some light in all directions and the path of the light through colloidal dispersion becomes visible to observer standing at right angles to its path.
iii. The phenomenon of scattering of light by colloidal particles and making path of light visible through the dispersion is referred as Tyndall effect and the bright cone of the light is called Tyndall cone.
iv. Tyndall effect is observed only when the following conditions are satisfied.
v. Significance of Tyndall effect:
b. Brownian motion:
i. The colloidal or microscopic particles undergo ceaseless random zig-zag motion in all directions in a fluid. This motion of dispersed phase particles is called Brownian motion.
ii. Cause of Brownian motion:
c. Types of emulsion:
iii. There are two types of emulsions:
a. Emulsion of oil in water (o/w type): An emulsion in which dispersed phase is oil and dispersion medium is water is called emulsion of oil in water.
e.g. 1. Milk consists of particles of fat dispersed in water.
2. Other examples include vanishing cream, paint, etc.
b. Emulsion of water in oil (w/o type): An emulsion in which dispersed phase is water and dispersion medium is oil is called emulsion of water in oil.
e.g. 1. Cod liver oil consists of particles of water dispersed in oil.
2. Some other examples of this type include butter, cream, etc.
d. Hardy-Schulze rule:
i. Generally, greater the valency of the flocculating ion added, greater is its power to cause precipitation. This is known as Hardy-Schulze rule.
ii. In the coagulation of negative sol, the flocculating power follows the following order:
Al3+ > Ba2+ > Na+
iii. Similarly, in the coagulation of positive sol, the flocculating power is in the following order:
[Fe (CN)6]4- > PO43- > SO42- > Cl–
Question G.
Explain Electrophoresis in brief with the help of diagram. What are its applications ?
Answer:
i. Electrophoresis: Electrophoresis set up is shown in the diagram below.
ii. Applications of electrophoresis:
Question H.
Explain why finely divided substance is more effective as adsorbent?
Answer:
Hence, finely divided substance is more effective as adsorbent.
Question I.
What is the adsorption Isotherm?
Answer:
The relationship between the amount of a substance adsorbed per unit mass of adsorbent and the equilibrium pressure (in case of gas) or concentration (in case of solution) at a given constant temperature is called an adsorption isotherm.
Question J.
Aqueous solution of raw sugar, when passed over beds of animal charcoal, becomes colourless. Explain.
Answer:
Question K.
What happens when a beam of light is passed through a colloidal sol?
Answer:
i. When a beam of light is passed through colloidal sol, it is observed that the colloidal particles scatter some of the incident light in all directions.
ii. Because of this scattering of light, the path of light through the colloidal dispersion becomes visible to observer standing at right angles to its path and the phenomenon is known as Tyndall effect.
iii.
Question L.
Mention factors affecting adsorption of gas on solids.
Answer:
Adsorption of gases on solids depends upon the following factors:
Question M.
Give four uses of adsorption.
Answer:
i. Catalysis (Heterogeneous catalysis):
ii. Gas masks:
iii. Control of humidity: Silica and alumina gels are good adsorbents of moisture.
iv. Production of high vacuum:
Question N.
Explain Bredig’s arc method.
Answer:
Question O.
Explain the term emulsions and types of emulsions.
Answer:
i. A colloidal system in which one liquid is dispersed in another immiscible liquid is called an emulsion.
ii. There are liquid-liquid colloidal systems in which both liquids are either completely or partially immiscible.
iii. There are two types of emulsions:
a. Emulsion of oil in water (o/w type): An emulsion in which dispersed phase is oil and dispersion medium is water is called emulsion of oil in water.
e.g. 1. Milk consists of particles of fat dispersed in water.
2. Other examples include vanishing cream, paint, etc.
b. Emulsion of water in oil (w/o type): An emulsion in which dispersed phase is water and dispersion medium is oil is called emulsion of water in oil.
e.g. 1. Cod liver oil consists of particles of water dispersed in oil.
2. Some other examples of this type include butter, cream, etc.
4. Explain the following :
Question A.
A finely divided substance is more effective as adsorbent.
Answer:
Question B.
Freundlich adsorption isotherm, with the help of a graph.
Answer:
Graphical representation of the Freundlich adsorption isotherm:
i. Freundlich proposed the following empirical equation for adsorption of a gas on solid.
\(\frac{x}{\mathrm{~m}}\) = k P1/n (n > 1) ………(i)
where,
x = Mass of the gas adsorbed
m = Mass of the adsorbent
\(\frac{x}{\mathrm{~m}}\) = Mass of gas adsorbed per unit mass of adsorbent
P = Equilibrium pressure
k and n are constants which depend on the nature of adsorbate, adsorbent and temperature.
ii. The graphical representation of Freundlich equation is as shown in the adjacent plot of x/m vs ‘P’.
iii. In case of solution, P in the equation (i) is replaced by the concentration (C) and thus,
\(\frac{x}{\mathrm{~m}}\) = k C1/n ………(ii)
iv. By taking logarithm on both sides of the equation (ii),
we get
log \(\frac{x}{\mathrm{~m}}\) = log k + \(\frac{1}{n}\) log C ……..(iii)
v. On plotting a graph of log \(\frac{x}{\mathrm{~m}}\) against log C or log P, a straight line is obtained as shown in the adjacent plot. The slope of the straight line is and intercept on Y-axis is log k.
vi. The factor \(\frac{1}{n}\) ranges from 0 to 1. Equation (iii) holds good over limited range of pressures.
a. When \(\frac{1}{n}\) → 0, \(\frac{x}{\mathrm{~m}}\) → constant, the adsorption is independent of pressure.
b. When \(\frac{1}{n}\) = 1, \(\frac{x}{\mathrm{~m}}\) = k P, i.e., \(\frac{x}{\mathrm{~m}}\) ∝ P, the adsorption varies directly with pressure.
c. The experimental isotherms tend to saturate at high pressure.
5. Distinguish between the following :
Question A.
Adsorption and absorption. Give one example.
Answer:
Adsorption:
Absorption:
Question B.
Physisorption and chemisorption. Give one example.
Answer:
Physisorption:
Chemisorption:
6. Adsorption is surface phenomenon. Explain.
Answer:
Consider a surface of a liquid or a solid.
Hence, adsorption is a surface phenomenon.
7. Explain how the adsorption of gas on solid varies with
a. nature of adsorbate and adsorbent
b. surface area of adsorbent
Answer:
i. a. Nature of adsorbate:
1. All solids adsorb gases to some extent. It is observed that gases having high critical temperature liquify easily and can be readily adsorbed.
2. The gases such as SO2, Cl2, NH3 which are easily liquefiable are adsorbed to a larger extent as compared to gases such as N2, O2, H2, etc. which are difficult to liquify.
3. Thus, the amount of gas adsorbed by a solid depends on the nature of the adsorbate gas i.e., whether it is easily liquefiable or not.
b. Nature of adsorbent: Substances which provide large surface area for a given mass are effective as adsorbents and adsorb appreciable volumes of gases.
e.g. Silica gel and charcoal are effective adsorbents due to their porous nature.
ii. Surface area of the adsorbent:
Note: Critical temperature of some gases and volume adsorbed.
8. Explain two applications of adsorption.
Answer:
i. Catalysis (Heterogeneous catalysis):
ii. Gas masks:
9. Explain micelle formation in soap solution.
Answer:
10. Draw labelled diagrams of the following :
a. Tyndall effect
b. Dialysis
c. Bredig’s arc method
d. Soap micelle
Answer:
a. Tyndall effect:
b. Dialysis:
c. Bredig’s arc method:
d. Soap micelle:
Activity :
Collect the information about methods to study surface chemistry.
Answer:
Following are the few methods that are employed to study surface chemistry.
i. X-ray photoelectron spectroscopy:
It is a surface-sensitive spectroscopic technique which is used to measure elemental composition of the surface, to determine elements that are present as contaminants on the surface, etc.
ii. Auger electron spectroscopy:
It is a common analytical technique which is used to study surfaces of materials.
iii. Temperature programmed desorption (TPD):
Adsorbed molecules get desorbed when the surface temperature is increased. TPD technique is used to observe these desorbed molecules and helps in providing information about binding energy between the adsorbate and adsorbent.
iv. Scanning Electron Microscopy:
In this technique, a scanning electron microscope is used to focus electron beam over the surface of the sample to be examined. The electron beam interacts with the sample and an image is obtained. This image provides information about surface structure and composition of the sample.
[Note: Students are expected to collect additional information about surface chemistry on their own.]
11th Chemistry Digest Chapter 11 Adsorption and Colloids Intext Questions and Answers
Can you tell? (Textbook Page No. 160)
Question 1.
What is adsorption?
Answer:
Adsorption is the phenomenon of accumulation of higher concentration of one substance on the surface of another (in bulk) due to unbalanced/unsatisfied attractive forces on the surface.
Try this. (Textbook Page No. 161)
Question 1.
Dip a chalk in ink. What do you observe?
Answer:
When a chalk is dipped in ink, it is observed that the ink molecules are adsorbed at the surface of chalk and the surface becomes coloured, while the solvent of the ink goes deeper into the chalk due to absorption.
Internet my friend. (Textbook Page No. 172)
Question i.
Brownian motion
Answer:
Students can search relevant videos on YouTube to visualize Brownian motion.
Question ii.
Collect information about Brownian motion.
Answer:
i. The colloidal or microscopic particles undergo ceaseless random zig-zag motion in all directions in a fluid. This motion of dispersed phase particles is called Brownian motion.
ii. Cause of Brownian motion:
Internet my friend. (Textbook Page No. 172)
Question 1.
Collect information about surface chemistry.
Answer:
[Note: Students are expected to collect additional information about surface chemistry on their own.]
Activity. (Textbook Page No. 172)
Question 1.
Calculate surface area to volume ratio of spherical particle. See how the ratio increases with the reduction of radius of the particle. Plot the ratio against the radius.
Answer:
The graph below shows that as the radius of the spherical particle decreases, the surface to volume ratio increases steadily.
Chapter 11 Adsorption and Colloids Textbook Exercise Questions and Answers.
1. Choose the correct option.
Question A.
The size of colloidal particles lies between
a. 10-10 m and 10-9 m
b. 10-9 m and 10-6 m
c. 10-6 m and 10-4 m
d. 10-5 m and 10-2 m
Answer:
b. 10-9 m and 10-6 m
Question B.
Gum in water is an example of
a. true solution
b. suspension
c. lyophilic sol
d. lyophobic sol
Answer:
c. lyophilic sol
Question C.
In Haber process of production of ammonia K2O is used as
a. catalyst
b. inhibitor
c. promotor
d. adsorbate
Answer:
c. promotor
Question D.
Fruit Jam is an example of-
a. sol
b. gel
c. emulsion
d. true solution
Answer:
b. gel
2. Answer in one sentence :
Question A.
Name type of adsorption in which van der Waals focres are present.
Answer:
Physical adsorption or physisorption.
Question B.
Name type of adsorption in which compound is formed.
Answer:
Chemical adsoiption or chemisorption.
Question C.
Write an equation for Freundlich adsorption isotherm.
Answer:
Freundlich proposed the following empirical equation for adsorption of a gas on solid.
\(\frac{x}{\mathrm{~m}}\) = k P1/n (n > 1) ……(i)
where,
x = Mass of the gas adsorbed
m = Mass of the adsorbent
\(\frac{x}{\mathrm{~m}}\) = Mass of gas adsorbed per unit mass of adsorbent
P = Equilibrium pressure
k and n are constants which depend on the nature of adsorbate, adsorbent and temperature.
3. Answer the following questions:
Question A.
Define the terms:
a. Inhibition
b. Electrophoresis
c. Catalysis.
Answer:
a. Inhibition:
The phenomenon in which the rate of chemical reaction is reduced by an inhibitor is called inhibition.
b. Electrophoresis:
The movement of colloidal particles under an applied electric potential is called electrophoresis.
c. Catalysis:
The phenomenon of increasing the rate of a chemical reaction with the help of a catalyst is known as catalysis.
Question B.
Define adsorption. Why students can read blackboard written by chalks?
Answer:
Hence, students can read blackboard written by chalks.
Question C.
Write characteristics of adsorption.
Answer:
Following are the characteristics of adsorption:
Question D.
Distinguish between Lyophobic and Lyophilic sols.
Answer:
Lyophobic sols (colloids):
Lyophilic sols (colloids):
Question E.
Identify dispersed phase and dispersion medium in the following colloidal dispersions.
a. milk
b. blood
c. printing ink
d. fog
Answer:
| Colloidal dispersion | Dispersed phase | Dispersion medium |
| Milk | Liquid | Liquid |
| Blood | Solid | Liquid |
| Printing ink | Solid | Liquid |
| Fog | Liquid | Gas |
Write notes on :
a. Tyndall effect
b. Brownian motion
c. Types of emulsion
d. Hardy-Schulze rule
Answer:
a. Tyndall effect:
i. Tyndall observed that when light passes through true solution, the path of light through it cannot be detected.
ii. However, if the light passes through a colloidal dispersion, the particles scatter some light in all directions and the path of the light through colloidal dispersion becomes visible to observer standing at right angles to its path.
iii. The phenomenon of scattering of light by colloidal particles and making path of light visible through the dispersion is referred as Tyndall effect and the bright cone of the light is called Tyndall cone.
iv. Tyndall effect is observed only when the following conditions are satisfied.
v. Significance of Tyndall effect:
b. Brownian motion:
i. The colloidal or microscopic particles undergo ceaseless random zig-zag motion in all directions in a fluid. This motion of dispersed phase particles is called Brownian motion.
ii. Cause of Brownian motion:
c. Types of emulsion:
iii. There are two types of emulsions:
a. Emulsion of oil in water (o/w type): An emulsion in which dispersed phase is oil and dispersion medium is water is called emulsion of oil in water.
e.g. 1. Milk consists of particles of fat dispersed in water.
2. Other examples include vanishing cream, paint, etc.
b. Emulsion of water in oil (w/o type): An emulsion in which dispersed phase is water and dispersion medium is oil is called emulsion of water in oil.
e.g. 1. Cod liver oil consists of particles of water dispersed in oil.
2. Some other examples of this type include butter, cream, etc.
d. Hardy-Schulze rule:
i. Generally, greater the valency of the flocculating ion added, greater is its power to cause precipitation. This is known as Hardy-Schulze rule.
ii. In the coagulation of negative sol, the flocculating power follows the following order:
Al3+ > Ba2+ > Na+
iii. Similarly, in the coagulation of positive sol, the flocculating power is in the following order:
[Fe (CN)6]4- > PO43- > SO42- > Cl–
Question G.
Explain Electrophoresis in brief with the help of diagram. What are its applications ?
Answer:
i. Electrophoresis: Electrophoresis set up is shown in the diagram below.
ii. Applications of electrophoresis:
Question H.
Explain why finely divided substance is more effective as adsorbent?
Answer:
Hence, finely divided substance is more effective as adsorbent.
Question I.
What is the adsorption Isotherm?
Answer:
The relationship between the amount of a substance adsorbed per unit mass of adsorbent and the equilibrium pressure (in case of gas) or concentration (in case of solution) at a given constant temperature is called an adsorption isotherm.
Question J.
Aqueous solution of raw sugar, when passed over beds of animal charcoal, becomes colourless. Explain.
Answer:
Question K.
What happens when a beam of light is passed through a colloidal sol?
Answer:
i. When a beam of light is passed through colloidal sol, it is observed that the colloidal particles scatter some of the incident light in all directions.
ii. Because of this scattering of light, the path of light through the colloidal dispersion becomes visible to observer standing at right angles to its path and the phenomenon is known as Tyndall effect.
iii.
Question L.
Mention factors affecting adsorption of gas on solids.
Answer:
Adsorption of gases on solids depends upon the following factors:
Question M.
Give four uses of adsorption.
Answer:
i. Catalysis (Heterogeneous catalysis):
ii. Gas masks:
iii. Control of humidity: Silica and alumina gels are good adsorbents of moisture.
iv. Production of high vacuum:
Question N.
Explain Bredig’s arc method.
Answer:
Question O.
Explain the term emulsions and types of emulsions.
Answer:
i. A colloidal system in which one liquid is dispersed in another immiscible liquid is called an emulsion.
ii. There are liquid-liquid colloidal systems in which both liquids are either completely or partially immiscible.
iii. There are two types of emulsions:
a. Emulsion of oil in water (o/w type): An emulsion in which dispersed phase is oil and dispersion medium is water is called emulsion of oil in water.
e.g. 1. Milk consists of particles of fat dispersed in water.
2. Other examples include vanishing cream, paint, etc.
b. Emulsion of water in oil (w/o type): An emulsion in which dispersed phase is water and dispersion medium is oil is called emulsion of water in oil.
e.g. 1. Cod liver oil consists of particles of water dispersed in oil.
2. Some other examples of this type include butter, cream, etc.
4. Explain the following :
Question A.
A finely divided substance is more effective as adsorbent.
Answer:
Question B.
Freundlich adsorption isotherm, with the help of a graph.
Answer:
Graphical representation of the Freundlich adsorption isotherm:
i. Freundlich proposed the following empirical equation for adsorption of a gas on solid.
\(\frac{x}{\mathrm{~m}}\) = k P1/n (n > 1) ………(i)
where,
x = Mass of the gas adsorbed
m = Mass of the adsorbent
\(\frac{x}{\mathrm{~m}}\) = Mass of gas adsorbed per unit mass of adsorbent
P = Equilibrium pressure
k and n are constants which depend on the nature of adsorbate, adsorbent and temperature.
ii. The graphical representation of Freundlich equation is as shown in the adjacent plot of x/m vs ‘P’.
iii. In case of solution, P in the equation (i) is replaced by the concentration (C) and thus,
\(\frac{x}{\mathrm{~m}}\) = k C1/n ………(ii)
iv. By taking logarithm on both sides of the equation (ii),
we get
log \(\frac{x}{\mathrm{~m}}\) = log k + \(\frac{1}{n}\) log C ……..(iii)
v. On plotting a graph of log \(\frac{x}{\mathrm{~m}}\) against log C or log P, a straight line is obtained as shown in the adjacent plot. The slope of the straight line is and intercept on Y-axis is log k.
vi. The factor \(\frac{1}{n}\) ranges from 0 to 1. Equation (iii) holds good over limited range of pressures.
a. When \(\frac{1}{n}\) → 0, \(\frac{x}{\mathrm{~m}}\) → constant, the adsorption is independent of pressure.
b. When \(\frac{1}{n}\) = 1, \(\frac{x}{\mathrm{~m}}\) = k P, i.e., \(\frac{x}{\mathrm{~m}}\) ∝ P, the adsorption varies directly with pressure.
c. The experimental isotherms tend to saturate at high pressure.
5. Distinguish between the following :
Question A.
Adsorption and absorption. Give one example.
Answer:
Adsorption:
Absorption:
Question B.
Physisorption and chemisorption. Give one example.
Answer:
Physisorption:
Chemisorption:
6. Adsorption is surface phenomenon. Explain.
Answer:
Consider a surface of a liquid or a solid.
Hence, adsorption is a surface phenomenon.
7. Explain how the adsorption of gas on solid varies with
a. nature of adsorbate and adsorbent
b. surface area of adsorbent
Answer:
i. a. Nature of adsorbate:
1. All solids adsorb gases to some extent. It is observed that gases having high critical temperature liquify easily and can be readily adsorbed.
2. The gases such as SO2, Cl2, NH3 which are easily liquefiable are adsorbed to a larger extent as compared to gases such as N2, O2, H2, etc. which are difficult to liquify.
3. Thus, the amount of gas adsorbed by a solid depends on the nature of the adsorbate gas i.e., whether it is easily liquefiable or not.
b. Nature of adsorbent: Substances which provide large surface area for a given mass are effective as adsorbents and adsorb appreciable volumes of gases.
e.g. Silica gel and charcoal are effective adsorbents due to their porous nature.
ii. Surface area of the adsorbent:
Note: Critical temperature of some gases and volume adsorbed.
8. Explain two applications of adsorption.
Answer:
i. Catalysis (Heterogeneous catalysis):
ii. Gas masks:
9. Explain micelle formation in soap solution.
Answer:
10. Draw labelled diagrams of the following :
a. Tyndall effect
b. Dialysis
c. Bredig’s arc method
d. Soap micelle
Answer:
a. Tyndall effect:
b. Dialysis:
c. Bredig’s arc method:
d. Soap micelle:
Activity :
Collect the information about methods to study surface chemistry.
Answer:
Following are the few methods that are employed to study surface chemistry.
i. X-ray photoelectron spectroscopy:
It is a surface-sensitive spectroscopic technique which is used to measure elemental composition of the surface, to determine elements that are present as contaminants on the surface, etc.
ii. Auger electron spectroscopy:
It is a common analytical technique which is used to study surfaces of materials.
iii. Temperature programmed desorption (TPD):
Adsorbed molecules get desorbed when the surface temperature is increased. TPD technique is used to observe these desorbed molecules and helps in providing information about binding energy between the adsorbate and adsorbent.
iv. Scanning Electron Microscopy:
In this technique, a scanning electron microscope is used to focus electron beam over the surface of the sample to be examined. The electron beam interacts with the sample and an image is obtained. This image provides information about surface structure and composition of the sample.
[Note: Students are expected to collect additional information about surface chemistry on their own.]
11th Chemistry Digest Chapter 11 Adsorption and Colloids Intext Questions and Answers
Can you tell? (Textbook Page No. 160)
Question 1.
What is adsorption?
Answer:
Adsorption is the phenomenon of accumulation of higher concentration of one substance on the surface of another (in bulk) due to unbalanced/unsatisfied attractive forces on the surface.
Try this. (Textbook Page No. 161)
Question 1.
Dip a chalk in ink. What do you observe?
Answer:
When a chalk is dipped in ink, it is observed that the ink molecules are adsorbed at the surface of chalk and the surface becomes coloured, while the solvent of the ink goes deeper into the chalk due to absorption.
Internet my friend. (Textbook Page No. 172)
Question i.
Brownian motion
Answer:
Students can search relevant videos on YouTube to visualize Brownian motion.
Question ii.
Collect information about Brownian motion.
Answer:
i. The colloidal or microscopic particles undergo ceaseless random zig-zag motion in all directions in a fluid. This motion of dispersed phase particles is called Brownian motion.
ii. Cause of Brownian motion:
Internet my friend. (Textbook Page No. 172)
Question 1.
Collect information about surface chemistry.
Answer:
[Note: Students are expected to collect additional information about surface chemistry on their own.]
Activity. (Textbook Page No. 172)
Question 1.
Calculate surface area to volume ratio of spherical particle. See how the ratio increases with the reduction of radius of the particle. Plot the ratio against the radius.
Answer:
The graph below shows that as the radius of the spherical particle decreases, the surface to volume ratio increases steadily.