Surface Chemistry – 2

1) Which one of the following substances acts as an emulsifier?
a) Common salt
b) Urea
c) Soap
d) Oils

2) In which one of the following properties do emulsions differ from colloidal sols?
a) Tyndall effect
b) Brownian movement
c) Electrophoresis
d) Size of the particles of the dispersed phase

3) The cleaning action of soap is due to
a) Its dissociation into ions in water
c) The formation of associated colloids
d) Its action as an emulsifying agent

4) Which of the following is not an emulsifying agent?
a) Oil
b) Gum
c) Proteins
d) Agar agar

5) Cod liver oil is an example of
a) Oil in water emulsion
b) Water in oil emulsion
c) Both (a) and (b)
d) None of these

6) If the dispersed phase is a liquid and the dispersion medium is a solid, the dispersion is known as
a) A sol
b) A gel
c) An emulsion
d) A foam

7) Which is not an elastic gel ?
a) Gelatin
b) Agar agar
c) Starch
d) Silicic acid

8) Select the non elastic gel out of the following
a) Starch
b) Agar agar
c) Silicic acid
d) Gelatin

9) Elastic gels absorb water and swell when placed in contact with water. This property is called
a) Thixotropy
b) Weeping
c) Syneresis
d) Imbibition

10) Elastic gels are
a) Reversible
b) Irreversible
c) Both (a) and (b)
d) None of these

11) When a colloidal solution is observed under an ultra microscope, we see
a) Light scattered by colloidal particles
b) Size of colloidal particles
c) Shape of the colloidal particles
d) Relative size of the colloidal particles

12) The gold number is minimum in the case of
a) Gelatin
b) Egg albumin
c) Gum arabic
d) Starch

13) Which of the following reactions do not lead to the formation of a colloidal solution ?
d) All of these

14) The 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

15) Which of the following forms a colloidal solution in water?
a) NaCl
b) Glucose
c) Starch
d) Barium nitrate

16) Mist is an example of a colloidal system of
a) Liquid dispersed in gas
b) Gas dispersed in gas
c) Solid dispersed in gas
d) Solid dispersed in liquid

17) In colloidal state, particle size ranges from

18) Which of the following is a hydrophobic sol?
a) Starch solution
b) Gum solution
c) Protein solution
d) Arsenious sulphide sol

19) On the addition of one ml of 10% NaCl solution to 10ml gold sol in the presence of 0.25g of starch, the coagulation is just prevented. Starch has the gold number
a) 0.025
b) 0.25
c) 2.5
d) 250

20) Which of the following represent the phenomenon of syneresis?
a) Separation of the dispersed phase from the gel
b) Formation of a sol from a gel
c) Migration of colloid in an electric field
d) Process of converting gel into a true solution

21) Which of the following is required in the lowest concentration to coagulate a sol having positively charged colloidal particles?
a) KCl

22) Gelatin is mostly used in making ice cream in order to
a) Prevent making of a colloid
b) Stabilize the colloid and prevent crystallization
c) Stabilize the mixture
d) Enrich the aroma

23) A liquid which markedly scatters a beam of light (visible in a dark room) but leaves no residue when passed through a filter paper is best described as a
a) A suspension
b) A true solution
c) Lyophobic sol
d) Lyophilic sol

24) A colloidal system in which solid is dispersed in a liquid is called a
a) Precipitate
b) Sol
c) Emulsion
d) Gel

25) Which one of the following is a hydrophilic colloidal sol?
a) Barium sulphate sol
b) Arsenic sulphide sol
c) Starch solution
d) Silver chloride sol

26) The Tyndall effect is observed in a
a) Solution
b) Precipitate
c) Sol
d) Vapour

27) The electrolyte which can most effectively cause coagulation of a negatively charged As2S3 sol is
b) KCl

28) The best electrolyte for coagulation of As2S3 sol is
a) NaCl

29) The gold number is minimum in the case of
a) Gelatin
b) Egg albumin
c) Gum arabic
d) Starch

30) Swimming for a long time in salt water makes the skin of ones fingertips wrinkled. Which one of the following properties is responsible for this observation?
a) Osmosis
b) Dialysis
c) Electrodialysis
d) Coagulation

31) Fog is an example of a colloidal system of
a) Gas in liquid
b) Liquid in gas
c) Solid in liquid
d) Liquid in liquid

32) Which of the following is a hydrophilic colloidal sol?
a) Barium sulphate sol
b) Arsenious sulphide sol
c) Starch sol
d) Silver iodide sol

33) Point out the false statement.
b) Colloidal solutions are homogeneous systems
c) Colloids carry charge
d) Colloids show the Tyndall effect

34) The colloidal sols are purified by
a) Precipitation of colloidal particles
b) Coagulation
c) Dialysis
d) Flocculation

35) As2S3 sol is a
a) Positive colloid
b) Negative colloid
c) Neutral colloid
d) None of the above

36) Sulphur sol contains
a) Discrete sulphur atoms
b) Discrete sulphur molecules
c) Large aggregates of sulphur molecules
d) Water dispersed in solid sulphur

37) Which one of the following colloidal solutions is a positive sol?
a) Blood
b) Clay soil
c) Smoke
d) Gelatin in a strongly acidic solution

38) In the given four colloidal dispersions, the true hydrophobic colloid is
a) Starch
b) Gelatin
c) Gum
d) Sulphur

39) Cow milk is an example of a natural emulsion stabilized by
a) Fat
b) Water
c) Casein

40) The colour of the colloidal particles of gold obtained by different methods differ because of
a) Variable valency of gold
b) Different concentration of gold particles
c) Different types of impurities
d) Different diameters of colloidal particles

41) Crystalloids differ from colloids mainly in respect of their
a) Electrical behaviour
b) Particle size
c) Particle nature
d) Solubility

42) A liquid is found to scatter a beam of light but leaves no residue when passed through the filter paper. The liquid can be described as
a) A suspension
b) Oil
c) A colloidal sol
d) True solution

43) A colloidal solution is subjected to an electrical field. The particles move towards the anode. The coagulation of the same sol using NaCI is studied, solutions. Their coagulating power should be

44) Which one among the following sols is hydrophobic?
a) Gum
b) Gelatin
c) Starch
d) Sulphur

45) Which of the following constitutes an irreversible colloidal system with water as the dispersion medium?
a) Clay
b) Platinum
d) All of these

46) Peptization denotes the
a) Digestion of food
b) Hydrolysis of proteins
c) Breaking and dispersion into the colloidal state
d) Precipitation of solid from colloidal dispersion

47) Which of the following contain hydrophobic structure ?
a) Linseed oil
b) Lanolin
c) Glycogen
d) All of these

48) The cause of Brownian movement is
a) Heat changes in liquid state
b) Conventional currents
c) The impact of molecules of the dispersion medium on the colloidal particles
d) Attractive forces between the colloidal particles and molecules of dispersion medium

49) Lysione is not used as a/an
a) Germ killer
b) Treatment for eye diseases
c) Anti-cancer drug
d) All of these

50) The stability of a lyophilic colloid is due to which of the following?
a) The charge on their particles
b) The large size of their particles
c) The small size of their particles
d) A layer of dispersion medium

51) Brownian movement is found in a
a) Colloidal solution
b) Suspension
c) Saturated solution
d) Unsaturated solution

52) 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 sugar is dispersed in water

53) The random motion of colloidal particles is known as
a) Dialysis
b) Brownian movement
c) Electro-osmosis
d) Tyndall effect

54) Milk can be preserved by adding a few drops of
a) Formic acid solution
b) Formaldehyde solution
c) Acetic acid solution
d) Acetaldehyde solution

55) Which of the following are not intrinsic colloids ?
a) Peptisation
b) Hydrolysis
c) Ultrasonic dispersion
d) none of these

56) In coagulating the colloidal solution of which has the minimum coagulating value ?
a) NaCl
b) KCl

57) Cod liver oil is
a) Fat dispersed in water
b) Water dispersed in fat
c) Water dispersed in oil
d) Fat dispersed in fat

58) In which of the following is the Tyndall effect not observed ?
a) Suspensions
b) Emulsions
c) Sugar solutions
d) Gold solutions

59) Which of the following are macro-molecular colloids ?
a) Starch
b) Cellulose
c) Detergent
d) Both (a) and (b)

60) Lyophilic colloids are stable due to the
a) Charge on the particles
b) Large size of the particles
c) Small size of the particles
d) Layer of dispersion medium on the particles

61) Which one of the following will have the highest coagulating power for a ferric hydroxide sol?
a) NaCl

62) Point out the false statement
a) Brownian movement and the Tyndall effect is shown by colloidal solutions
b) The gold number is a measure of the protective power of a lyophillic colloid
c) The colloidal solution of a liquid in liquid is called gel
d) The Hardy-Schulze rule is related to coagulation

63) At CMC the surfactant molecules
a) Decompose
b) Become completely soluble
c) Associate
d) Dissociate

64) The size of colloidal particles is

65) The Tyndall effect is shown bya
a) Sol
b) Solution
c) Plasma
d) Precipitate

66) The gold number is associated with
a) Electrophoresis
b) Purple of Cassius
c) Protective colloids
d) The amount of pure gold

67) Which of the following ions can cause coagulation of proteins ?

68) In Brownian movement or motion, the paths of the particles are
a) Linear
b) Zig-zag
c) Uncertain
d) Curved

69) What is used for neutralizing the charge on a colloidal solution ?
a) Electrons
b) Electrolytes
c) Positively charged ions
d) Compounds

70) Cloud or fog is a colloidal system in which the dispersed phase and the dispersion medium are
a) Gas, liquid
b) Liquid, gas
c) Liquid, liquid
d) Solid, liquid

71) Which of the following is most effective in causing the coagulation of ferric hydroxide sol?
a) KCl

72) Blood may be purified by
a) Dialysis
b) Electro-osmosis
c) Coagulation
d) Filtration

73) Which one is an example of a micellar system ?
a) Soap + water
b) Rubber + benzene
c) Protein + water
d) None of these

74) The coagulation of 100 ml of a colloidal solution of gold is completely prevented by the addition of 0.25 g of a substance “X” to it before adding 1 ml of 10% NaCl solution. The gold number of “X” is
a) 0.25
b) 25
c) 250
d) 2.5

75) At isoelectric point
a) The colloidal particles become unchanged
b) The colloidal sol becomes highly stable
c) Peptisation can be carried out
d) None of these

76) The gold number was given by
a) Ostwald
b) Zsigmondy
c) Williams and Chang
d) Langmuir

77) The sedimentation potential is the reverse of the
a) Electro-osmosis
b) Electrophoresis
c) Electrokinetic potential
d) Dorn potential

78) Electro-osmosis was discovered by
a) Dorn
b) Reuss and Perrot
c) Freundlich
d) Langmuir

79) Agl is used for producing artificial rain because Agl
a) is easy to spray at high altitude
b) is easy to synthesise
c) Has a crystal structure similar to ice
d) is insoluble in water

80) All colloidal solutions show
a) Very high osmotic pressure
b) High osmotic pressure
c) Low osmotic pressure
d) No osmotic pressure

81) Which one of the following statements regarding catalysts is not true?
a) A catalyst remains unchanged in composition and quantity at the end of the reaction
b) A catalyst cannot initiate a reaction
c) A catalyst does not take part in a reaction
d) A catalyst does not alter the equilibrium in a reversible reaction

82) A homogeneous catalyst implies that
a) All reactants and products must be in the same phase
b) The reactants and the catalyst must be in the same phase
c) The products and the catalyst must be in the same phase
d) The composition of the reaction mixture must be homogeneous throughout

83) Which one of the following is an example of negative catalysis?

84) #@ Which one of the following is an example of homogeneous catalysis?

85) Which one of the following is an example of heterogeneous catalysis?
d) Cracking of hydrocarbons in presence of hydrogen by zeolite catalysts

86) The catalyst used in the Zeigler method for polymerization of ethylene is
b) Platinum
c) ZnO + CuO

87) In which of the following processes is platinum used as a catalyst?
a) Oxidation of ammonia to form nitric acid
b) Hardening of oil
c) Production of synthetic rubber
d) Synthesis of methanol

88) An example of an auto catalytic reaction is the
a) decomposition of nitroglycerine
d) Hydrogenation of vegetable oil using nickel catalyst

89) Glucose or fructose can be converted into ethanol in the presence of
a) Invertase
b) Zymase
c) Maltase
d) Diastase

90) The catalyst used in the manufacture of NH3 by Habers process is
a) Finely divided iron
b) Finely divided molybdenum
c) Finely divided nickel
d) Finely divided platinum

91) Which one of the following acts as a poison for the catalyst (anti-catalyst) in the contact process for the manufacture of sulphuric acid?
a) Sulphur
b) Arsenic sulphide
c) Arsenic oxide

92) Enzymes are
a) Substances made by chemists to activate washing powder
b) Very active vegetable catalysts
c) Catalysts found in living organisms
d) Synthetic catalysts

93) 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 in the substrate molecule
c) To change the shape of the substrate molecule
d) To raise the activation energy of the reaction

94) A catalyst in the finely divided state is more efficient because in this state
a) It has a larger activation energy
b) It has a larger surface area
c) It can react with one of the reactants more efficiently
d) Particle-molecule contact becomes easier

95) Intermediate compound formation theory is the mechanism of
a) Homogeneous catalysts
b) Heterogeneous catalysts
c) Auto-catalysis
d) Negative catalysis

96) Shape selective catalysts are so called because of
a) The shape of the catalysts
b) The specificity of the catalysts
c) The size of the pores of the catalysts which can trap only certain selected molecules
d) Their use for only some selected reactions

97) Which one of the following is a shape selective catalyst?
c) Hydrated zeolites
d) ZSM-5

98) Which of the following catalysts is used for preparing toluene by reacting benzene with methyl chloride?
a) Ni
c) Pd
d) Pt

99) A catalyst in the finely divided state is more efficient because in this state
a) It has a larger activation energy
b) It can react with one of the reactants more efficiently
c) It has a large surface area
d) All the above

100) An inhibitor is essentially
a) A negative catalyst
b) An autocatalyst
c) A homogeneous catalyst
d) A heterogeneous catalyst


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