Surface Chemistry Quiz | Chemistry Quiz
“The branch of physical chemistry, which deals the nature of surfaces and also with the chemical and physical processes which take place on the surfaces, is called surface chemistry”.
In surface chemistry, we study the phenomenon of adsorption, catalysis and colloidal properties.
Adsorption
(1) Definition: The phenomenon of attracting and retaining the molecules of a substance on the surface of a liquid or solid resulting into a higher concentration of the molecules on the surface is called adsorption.(2) Causes of adsorption: Unbalanced forces of attraction or free valencies which are present at the solid or liquid surface, have the property to attract and retain the molecules of a gas or a dissolved substance on to their surfaces with which they come in contact.
Example: Ammonia gas placed in contact with charcoal gets adsorbed on the charcoal whereas ammonia gas placed in contact with water gets absorbed into water,
Classification of adsorption
Adsorption can be classified into two categories as described below,
(1) Depending upon the concentration: In adsorption, the concentration of one substance is different at the surface of the other substance as compared to adjoining bulk or interior phase.
(i) Positive adsorption: If the concentration of adsorbate is more on the surface as compared to its concentration in the bulk phase then it is called positive adsorption.
Example: When a concentrated solution of KCl is shaken with blood charcoal, it shows positive adsorption.
(ii) Negative adsorption: If the concentration of the adsorbate is less than its concentration in the bulk then it is called negative adsorption.
Example: When a dilute solution of KCl is shaken with blood charcoal, it shows negative adsorption.
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Adsorption and Adsorption isotherm Quiz
1. When the temperature is raised, the viscosity of liquid decreases, this is because
(a) Decreased volume of the solution
(b) Increase in temperature increases the average kinetic energy of molecules, which overcome the attractive force between them
(c) Decreased covalent and hydrogen bond forces
(d) Increased attraction between molecules
SOL: (b) When the temperature is raised, the viscosity of liquid decreases, this is because increase in temperature increases the average kinetic energy of molecules which overcome the attractive force between them.
2. A solid acts as an adsorbent because it has
(a) A definite shape
(b) Small pores in it
(c) Unsaturated valencies
(d) A high lattice energy
SOL: C
3. Point out the wrong statement :
Physical adsorption is characterised by
(a) Attraction due to weak Vander Waal's forces
(b) Irreversible nature of adsorption
(c) Multimolecular adsorption layers
(d) Decrease in adsorption with increase in temperature
SOL: B
4. When the temperature is lowered and pressure is raised, the adsorption of a gas on a solid
(a) Decreases
(b) Increases
(c) Remains unaffected
(d) Decreases first then increases
SOL: B
5. In physical adsorption, the gas molecules are held on solid surface by
(a) Chemical forces
(b) Electrostatic forces
(c) Gravitational forces
(d) Vander Waal's forces
SOL: D
6. Adsorption is multilayer in the case of
(a) Physical adsorption
(b) Chemisorption
(c) Both
(d) None of both
SOL: A
7. Physical adsorption
(a) Involves the weak attractive interaction between the adsorbent and adsorbate
(b) Involves the chemical interactions between the adsorbent and adsorbate
(c) Is irreversible in nature
(d) Increases with increase of temperature
SOL: A
8. Physical adsorption is essentially quite appreciable
(a) At room temperature
(b) At higher temperature
(c) At lower temperature
(d) None of these
SOL: C
9. Adsorption increase when
(a) Temperature increases
(b) Temperature decreases
(c) Temperature remains constant
(d) None of these
SOL: (b) Adsorption increase when temperature decreases (Adsorption 1/Temperature)
10. In chemical adsorption, how many layers are adsorbed
(a) One (b) Two
(c) Multi (d) Zero
SOL: (a) In chemical adsorption, one layers are adsorbed.
11. Which of the following statements is not applicable to chemisorption
(a) It is slow
(b) It is irreversible
(c) It is highly specific
(d) It is independent of temperature
SOL: (d) Chemisorption first increases and then decreases with temperature.
12. Adsorption is always
(a) Endothermic
(b) Exothermic
(c) Either (a) or (b)
(d) None of these
SOL: (b) Adsorption is an exothermic process.
13. The colloidal system consisting of a liquid adsorbent in a solid adsorbate is termed as
(a) Aerosol (b) Sol
(c) Foam (d) Gel
SOL: B
14. Which of the following kinds of catalysis can be explained by the adsorption theory ?
(a) Homogeneous catalysis
(b) Acid base catalysis
(c) Heterogeneous catalysis
(d) Enzyme catalysis
SOL: (c) Heterogeneous catalysis can be explained by the adsorption theory.
15. Adsorption due to strong chemical forces is called
(a) Chemisorption
(b) Physiosorption
(c) Reversible adsorption
(d) Both (b) and (c)
SOL: (a) Adsorption due to strong chemical bond is called chemical adsorption or chemisorption or Langmuir adsorption.
Catalyst and Catalysis Quiz
16. In Haber's process for the manufacture of ammonia(a) Finely divided iron is used as catalyst
(b) Finely divided molybdenum is used as catalyst
(c) Finely divided nickel is used as catalyst
(d) No catalyst is necessary
SOL: (a)
17. Reactions in Zeolite catalysts depend on
(a) Pores (b) Apertures
(c) Size of cavities (d) All of these
SOL: (d) It is a shape-selective catalyst.
18. What is the role of a catalyst in a catalysed reaction
(a) Lowers the activation energy
(b) Increases the activation energy
(c) Affects the free energy change
(d) Affects the enthalpy change
SOL: (a) All substance have average energy and before the reaction occurs energy of the reactant should be higher than the average energy. We also know that catalyst lower the activation energy. Therefore, rate of reaction is increased.
19. The catalyst used in the lead chamber process of sulphuric acid manufacture is
(a) Platinum
(b) Oxide of nitrogen
(c) Nickel
(d) Vanadium compounds
SOL: (b)
20. The role of a catalyst in a reversible reaction is to
(a) Increase the rate of forward reaction
(b) Decrease the rate of backward reaction
(c) Alter the equilibrium constant of the reaction
(d) Allow the equilibrium to be achieved quickly
SOL: (d) An increase in rate of reaction in forward direction by a catalyst for a reaction in equilibrium brings in an increase in concentration of products and thus rate of backward reaction also increase to same magnitude and so allow the equilibrium to be achieved quickly.
21. The catalyst used in the contact process for the manufacturing of sulphuric acid is
(a) Copper
(b) Iron/aluminium oxide
(c) Vanadium pentoxide
(d) Platinized asbestos
SOL: (c)
22. For the functioning of enzymes which of the following statements is not correct
(a) An optimum temperature is needed
(b) An optimum pH is needed
(c) They are substrate specific
(d) They always increase activation energy
SOL: D
23. When a catalyst is added to a system the [
(a) Value of equilibrium constant is decreased
(b) The rate of forward reaction is increased and that of backward reaction is decreased
(c) Equilibrium concentrations are unchanged
(d) Equilibrium concentrations are increased
SOL: (c) Catalyst never change the equilibrium constant.
24. A catalyst can affect reversible reaction by
(a) Changing equilibrium
(b) Slowing forward reaction
(c) Attaining equilibrium in both direction
(d) None of these
SOL: C
25. The efficiency of an enzyme in catalysing a reaction is due to its capacity
(a) To form a strong enzyme-substrate complex
(b) To decrease the bond energies of substrate molecule
(c) To change the shape of the substrate molecule
(d) To lower the activation energy of the reaction
SOL: (d) Efficiency of catalysing property is inversely proportional of activation energy.
26. A catalyst is a chemical reaction
(a) Does not initiate a reaction
(b) Increases the activation energy of the reaction
(c) Changes the equilibrium constant of a reaction
(d) Does not change the rate of the reaction
SOL: A
27. Platinized asbestos is used as a catalyst in the manufacture of H2SO4. It is an example of
(a) Heterogeneous catalyst
(b) Autocatalyst
(c) Homogenous catalyst
(d) Induced catalyst
SOL: (a) Example of heterogeneous catalyst.
28. Addition of catalyst in a system
(a) Increases equilibrium concentrations
(b) No effect on equilibrium concentrations
(c) Decreases equilibrium concentrations
(d) Increases rate of forward reaction and decreases rate of backward reaction
SOL: (b) Catalyst is not effect on equilibrium concentrations.
29. In which of the following processes, platinum is used as a catalyst
(a) Oxidation of ammonia to form nitric acid
(b) Hardening of oils
(c) Production of synthetic rubber
(d) Synthesis of methanol
SOL: (a)
30. Enzymes are
(a) Micro-organisms
(b) Proteins
(c) Inorganic compounds
(d) Moulds
SOL: B
31. A biological catalyst is essentially
(a) An amino acid
(b) A carbohydrate
(c) The nitrogen molecule
(d) An enzyme
SOL: D
32. A catalyst added to a reaction mixture
(a) Increases the equilibrium constant
(b) Decreases the equilibrium constant
(c) Does not change the equilibrium constant
(d) None of these
SOL: C
33. Which of the following statements regarding catalyst is not true
(a) A catalyst remains unchanged in composition and quantity at the end of the reaction
(b) A catalyst can initiate a reaction
(c) A catalyst does not alter the equilibrium in a reversible reaction
(d) Catalyst are sometimes very specific in respect of reaction
SOL: B
34. The enzyme ptylin used for the digestion of food is present in
(a) Saliva
(b) Blood
(c) Intestine
(d) Adrenal glands
SOL: (a)Ptyline (enzyme) is present in saliva.
Colloids, Emulsion, Gel and Their properties with application Quiz
35. The stability of lyophilic colloids is due to
(a) Charge on their particles
(b) A layer of dispersion medium on their particles
(c) The smaller size of their particles
(d) The large size of their particles
SOL: (b) Lyophilic possesses solvent loving nature and thus a thin layer of dispersed phase is formed round sol particles.
36. Milk is a colloid in which
(a) A liquid is dispersed in liquid
(b) A solid is dispersed in liquid
(c) A gas is dispersed in liquid
(d) Some suger is dispersed in water
SOL: (a) Milk is a colloid of liquid (H20) dispersed in liquid (fat).
37. Smoke is an example of
(a) Gas dispersed in liquid (b) Gas dispersed in solid
(c) Solid dispersed in gas (d) Solid dispersed in solid
SOL: (c) Smoke is an example of solid dispersed in gas.
38. Gold number is minimum in case of
(a) Gelatin
(b) Egg albumin
(c) Gum Arabic
(d) Starch
SOL: A
39. Movement of colloidal particles under the influence of electrostatic field is
(a) Electrophoresis (b) Electrolysis
(c) Dialysis (d) Ionisation
SOL: (a) Movement of (charged) colloidal particles under the influence of electrostatic field is called electrophoresis due to opposite charge.
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40. Which of the following substances gives a positively charged sol
(a) Gold
(b) A metal sulphite
(c) Ferric hydroxide
(d) An acidic dye
SOL: (c)
41. Light scattering in colloidal particles is
(a) Visible to naked eye
(b) Not visible by any means
(c) Visible under ordinary microscope
(d) Visible under ultra-microscope
SOL: D
42. Flocculation value is expressed in terms of
(a) millimole per litre
(b) mole per litre
(c) gram per litre
(d) mole per milliliter
SOL: (a) Flocculation value is expressed in terms of millimole per litre.
43. Which of the following is an emulsifier
(a) Soap (b) Water
(c) Oil (d) NaCl
SOL: A
44. Suspensions are
(a) Visible to naked eye
(b) Invisible through microscope
(c) Not visible by any means
(d) Invisible under electron microscope
SOL: A
45. Gelatin is mostly used in making ice cream in order to
(a) Prevent making of colloid
(b) To stabilise the colloid and prevent crystallisation
(c) To stabilise mixture
(d) To enrich the aroma
SOL: (b) Gelatin is a protective colloid.
46. Which is a natural colloidal
(a) Sodium chloride (b) Urea
(c) Canesugar (d) Blood
SOL: D
47. Sodium stearate forms in water
(a) True solution
(b) A suspension
(c) An emulsion
(d) A colloidal solution
SOL: D
48. Blood contains
(a) Positively charged particles
(b) Negatively charged particles
(c) Neutral particles
(d) Negatively as well as positively charged particles
SOL: B
49. Brownian motion is due to
(a) Temperature fluctuation within the liquid phase
(b) Attraction and repulsion between charge on the colloidal
(c) Impact of molecules of the dispersion medium on the colloidal particles
(d) Convective currents
SOL: C
50. Milk can be preserved by adding a few drops of
(a) Formic acid solution
(b) Formaldehyde solution
(c) Acetic acid solution
(d) Acetaldehyde solution
SOL: (b) Milk can be preserved by adding a few drops of HCHO solution. HCHO is an emulsifier.
51. When a colloidal solution is observed under a microscope we can see
(a) Light scattered by colloidal particles
(b) Size of colloidal particles
(c) Shape of colloidal particles
(d) Relative size of the colloidal particles
SOL:
52. Property of the colloidal solution is due to
(a) Nature of dispersed phase
(b) Nature of dispersion medium
(c) Physical state of dispersed phase
(d) Temperature of the system
SOL: A
53. According to Graham, colloids are those substances which are
(a) Insoluble in water
(b) In solution do not pass through filter paper
(c) Of definite size of particles
(d) Separated from crystalloids by parchment paper
SOL: D
54. The reason for exhibiting Tyndall effect by the colloidal particle is
(a) Reflection of light
(b) Refraction of light
(c) Polarisation of light
(d) Scattering of light
SOL: (d) According to Graham, colloids are separated from crystalloids by parchment paper
55. Which of the following shows the maximum hydrophobic behaviour
(a) Glycerine (b) Stearic acid
(c) Glucose (d) Adenine
SOL: D
56. A liquid aerosol is a colloidal system of
(a) A liquid dispersed in a solid
(b) A liquid dispersed in a gas
(c) A gas dispersed in a liquid
(d) A solid dispersed in a gas
SOL: D
57. Gelatin is mixed in ice-cream
(a) As a coagulant
(b) For taste
(c) For colour
(d) As a protective colloid
SOL: (d) Gelatin is a protective colloid in ice-cream.
58. Which of the following is an example of `water in oil' type emulsion
(a) Butter (b) Milk
(c) Cream (d) Face cream
SOL: A
59. In which of the following Tyndall effect is not observed
(a) Suspensions (b) Emulsions
(c) Sugar solution (d) Gold sol
SOL: (c) Tyndall effect is not observed in sugar solution due to homogeneous nature.
60. Which of the following is a lyophilic colloid
(a) Milk (b) Gum
(c) Fog (d) Blood
SOL: B
61. Which characteristic is true in respect of colloidal particle
(a) They always have two phases
(b) They are only in liquid state
(c) They can't be electrolysed
(d) They are only hydrophilic
SOL: (a) Dispersion medium and dispersed phase are phase of colloid.
62. Gold number is a measure of the
(a) Protective action by a lyophilic colloid on a lyophobic colloid
(b) Protective action by a lyophobic colloid on a lyophilic colloid
(c) Number of of gold in a standard red gold sol
(d) Stability of gold sol
SOL: A
63. Sulphur sol contains
(a) Discrete sulphur atoms
(b) Discrete sulphur molecules
(c) Large agreegates of sulphur molecules
(d) Water dispersed in solid sulphur
SOL: C
64. Pick out the statement which is not relevant in the discussion of colloids
(a) Sodium aluminium silicate is used in the softening of hard water
(b) Potash alum is used in shaving rounds and as antiseptic in medicine
(c) Artificial rain is caused by throwing electrified sand on the clouds from an aeroplane
(d) Deltas are formed at a place where the river pours its water into the sea
SOL: A
65. When excess of electrolyte is added to a colloid it
(a) Coagulates
(b) Precipitates
(c) Gets diluted
(d) Does not change
SOL: A
66. The shape of colloidal particles is
(a) Sphere like (b) Rod like
(c) Disc like (d) All of these
SOL: d
67. The example of heteropolar sol is
(a) Starch sol in water
(b) Rubber sol in water
(c) Protein sol in water
(d) Sulphur sol
SOL: (c) Protein sol in water is a example of heteropolar sol.
68. In Bredig's arc method some alkali is added because
(a) It increases electrical conductance
(b) To obtain molecular colloid
(c) To obtain colloidal particles of same size
(d) To stabilise the sol
SOL: (d) For stabilise the sol.
69. Which one of the following is not a colloid
(a) Milk (b) Blood
(c) Solution of urea (d) Ice cream
SOL: (c)Solution of urea is not a colloid.
70. Milk is an example of
(a) Pure solution (b) Emulsion
(c) Gel (d) Suspension
SOL: B
71. Dialysis is the process of separation of
(a) Suspended particles from colloids
(b) Suspended particles from crystalloids
(c) Colloidal particles from crystalloids
(d) Colloidal particles from gel
SOL:C
72. Minimum concentration of electrolyte which can precipitate any sol is
(a) Peptization value (b) Gold number
(c) Avogadro's number (d) Flocculation value
SOL: D
73. An example of an associated colloid is
(a) Milk
(b) Soap solution
(c) Rubber latex
(d) Vegetable oil
SOL: B
74. The movement of colloidal particles towards the oppositely charged electrodes on passing electricity is known as
(a) Cataphoresis
(b) Tyndall effect
(c) Brownian movement
(d) None of these
SOL: A
75. Tyndall effect is shown by[
(a) Sol
(b) Solution
(c) Plasma
(d) Precipitation
SOL:A
76. Colloidal solutions of gold prepared by different methods have different colours owing to
(a) The difference in the size of the colloidal particles
(b) The fact that gold exhibits a variable valency of + 1 and + 3
(c) Different concentrations of gold
(d) Presence of different types of foreign particles depending upon the method of preparation of the colloid
SOL: A
77. Which of the following is the best protective colloid
(a) Gelatin (Gold No. = 0.005)
(b) Gum arabic (Gold No. = 0.15)
(c) Egg albumin (Gold No. = 0.08)
(d) None of these
SOL: (a)
78. A catalyst is a substance which
(a) Is always in the same phase as in the reactions
(b) Alters the equilibrium in a reaction
(c) Does not participate in the reaction but alters the rate of reaction
(d) Participates in the reaction and provide an easier pathway for the same
SOL: (c) A catalyst does not participate in the reaction but alters the rate of reaction.
79. Cod liver oil is
(a) An emulsion (b) Solution
(c) Colloidal solution (d) Suspension
SOL: (a) A colloid of liquid in liquid is called emulsion cod liver oil is such an emulsion.
80. Paste is
(a) Suspension of solid in a liquid
(b) Mechanical dispersion of a solid in liquid
(c) Colloidal solution of a solid in solid
(d) None of these
SOL: (a) Suspension of solid in a liquid.
Critical Thinking Questions Quiz
81. Which one of the following is not represented by sols(a) Absorption
(b) Tyndall effect
(c) Flocculation
(d) Paramagnetism
SOL: (d) Absorption, Tyndall effect and flocculation all are related to sol but paramagnetism is not represented by sol.
82. Colloidal solution of arsenious sulphide can be prepared by
(a) Electrodispersion method
(b) Peptization
(c) Double decomposition
(d) Hydrolysis]
SOL: (c) Arsenious sulphide can be prepared by double decomposition
83. The capacity to bring about coagulation increases with
(a) Ionic radii
(b) Atomic radii
(c) Valency of an ion
(d) Size of an ion
SOL: (c) The amount of electrolyte required to coagulate a fixed amount of a sol depends upon the valency of flocculating ion.
84. Gold number gives
(a) The amount of gold present in the colloid
(b) The amount of gold required to break the colloid
(c) The amount of gold required to protect the colloid
(d) None of these
SOL: (d) Gold no. is a measure of protective power of a lyophillic colloid.
85. Point out the false statement[
(a) Brownian movement and Tyndall effect is shown by colloidal systems
(b) Gold number is a measure of the protective power of a lyophilic colloid
(c) The colloidal solution of a liquid in liquid is called is gel
(d) Hardy–Schulze rule is related with coagulation
SOL: (c) The colloidal solution of liquid in liquid is called emulsion not gel.
