CBSE Questions for Class 12 Engineering Chemistry Surface Chemistry Quiz 12 - MCQExams.com

What can be observed when sunlight is passed through a colloidal solution?
  • Adsorption
  • Coagulation
  • Tyndall effect
  • Brownian motion
Which of the following statements is incorrect with respect to physisorption?
  • The forces involved are van der Waal's forces
  • More easily liquifiable gases are adsorbed easily
  • Under high pressure it results into multi-molecular layer on adsorbent surface
  • $$\Delta H_{adsorption}$$ is low and $$+$$ve
Oil floats on water. The most accurate reason for this is:
  • oil is less dense than water
  • oil is immiscible (does not dissolve) in water
  • oil is both less dense and immiscible with water
  • water is heavier than oil
What is the use of colloidal copper ?
  • In treatment of cancer
  • In treatment of syphilis
  • Diagnostic agent for paresis
  • None of these
In an adsorption experiment, a graph between log$$\left(\displaystyle\frac{x}{m}\right)$$ versus log $$p$$ is found to be linear with slope of $$45^o$$. The intercept on log$$\left(\displaystyle\frac{x}{m}\right)$$ axis was found to $$0.3010$$. The amount of the gas adsorbed per gram of charcoal under the pressure of $$0.5$$ atm will be:
  • $$1.0$$
  • $$2.0$$
  • $$0.50$$
  • $$0.25$$
Activated charcoal is used to remove coloring matter from pure substances. It works by:
  • oxidation
  • reduction
  • bleaching
  • adsorption
A colloidal system having a solid substance as a dispersed phase and a liquid as a dispersion medium is classified as:
  • solid sol
  • gel
  • emulsion
  • sol
Which of the following process is responsible for formation of delta at a place where river meets the sea?
  • Emulsification
  • Coagulation
  • Colloidal formation
  • Peptisation
The heats of adsorption (in $$kJ/mol$$) in physisorption or physical adsorption lie in the range of:
  • $$40 - 400$$
  • $$40 - 100$$
  • $$10 - 40$$
  • $$200 - 400$$
Which is used for ending charge on colloidal solutions?
  • Electrons
  • Electrolysis
  • Positively charged ions
  • Compounds
Bredig's arc method is used for the preparation of colloidal solution of:
  • metals like silver, gold, etc
  • organic compounds
  • two liquids
  • inorganic compounds
To stop bleeding from an injury ferric chloride can be applied
Which comment about the statement is justified?
  • It is not true, ferric chloride is a poison
  • It is true, $${Fe}^{3+}$$ ions coagulate blood which is negatively charged sol
  • It is not true, $${Cl}^{-}$$ ions from positively charged sol, profuse bleeding takes place
  • It is true, coagulation takes place because of formation of negatively charged sol with $${Cl}^{-}$$ ions.
  • It is not true, ferric chloride is ionic and gets into blood stream
Peptization of $$Sn{ O }_{ 2 }$$ by $$NaOH$$ gives:
  • $$\left[ Sn{ O }_{ 2 } \right] Sn{ O }_{ 3 }^{ 2- }:2{ Na }^{ + }$$
  • $$ \left[ Sn{ O }_{ 2 } \right] { Sn }^{ 4+ }:{ O }_{ }^{ 2- }$$
  • $$\left[ Sn{ O }_{ 2 } \right] Na:{ OH }^{ - }$$
  • $$\left[ Sn{ O }_{ 2 } \right] { Sn }^{ 4+ }:{ OH }^{ - }$$
The name aquadag is given to the colloidal solution of:
  • copper in water
  • platinum in water
  • gold in water
  • graphite in water
Which of the following reactions is not used for the preparation of a colloidal solution?
  • $$2Au{ Cl }_{ 3 }+3Sn{ Cl }_{ 2 }\longrightarrow 3Sn{ Cl }_{ 4 }+2Au$$
  • $$Fe{ Cl }_{ 3 }+3{ H }_{ 2 }O\longrightarrow Fe{ \left( OH \right) }_{ 3 }+3HCl$$
  • $$2Mg+{ CO }_{ 2 }\longrightarrow 2MgO+C$$
  • $$2{ H }_{ 2 }S+2S{ O }_{ 2 }\longrightarrow 2{ H }_{ 2 }O+3S$$
Silver iodide is used for producing artificial rains because $$AgI$$:
  • is easy to spray at high altitude
  • is insoluble in water
  • is easy to synthesize
  • has crystals similar to ice
The fresh precipitate can be transformed in colloidal solution by:
  • peptization
  • coagulation
  • diffusion
  • none of these
Cotrell precipitator works on the principle of:
  • distribution law
  • addition of electrolyte
  • neutralisation of charge on colloids
  • Le Chatelier's principle
Which one of the following is not a correct statement?
  • Physical adsorption is reversible in nature.
  • Physical adsorption involves Van der Waals forces.
  • Rate of chemical adsorption increases with increase of temperature.
  • High activation energy is involved in chemical adsorption.
Which of the following factors are responsible for the increase in the rate of a surface catalyzed reaction?
(i) A catalyst provides proper orientation for the reactant molecules to react.
(ii) The heat of adsorption of reactants on a catalyst helps reactant molecules to overcome activation energy.
(iii) The catalyst increases the activation energy of the reaction.
  • (i) and (iii)
  • (i) and (ii)
  • (ii) and (iii)
  • (i), (ii) and (iii)
Multiple Answers Type Objective Questions :
Which of the following act as negative catalyst?
  • Ethanol in oxidation of chloroform
  • Tetraethyl lead used as antiknocking agent
  • Glycerol in the decomposition of $$H_2O_2$$
  • $$Fe$$ in the formation of ammonia by Haber process
Which of the following represents physical adsorption ?
Which of the following are correct about a catalyst ? 
  • It participates in the reaction but is recovered at last
  • It does not affect $$\Delta G$$
  • It does not affect $$\Delta H$$
  • It alters the mechanism of reaction
Which of the following is homogeneous?
  • Milk
  • Paint
  • Shampoo
  • None of these
Choose the wrong statement from the following.
  • $$Ti{ O }_{ 2 }$$ is used in the pigment industry
  • $$Mn{ O }_{ 2 }$$ is used in dry battery cells
  • $${ V }_{ 2 }{ O }_{ 5 }$$ catalyses the oxidation of $$S{ O }_{ 2 }$$ in the manufacture of sulphuric acid
  • Ziegler-Natta catalyst is used in the manufacture of high density polyethylene
  • The 'silver' UK coins are made of $${ Ag }/{ Ni }$$ alloy
Activated charcoal is prepared by: 
  • Adding $$Ba_3(PO_4)_2$$ to charcoal
  • Treatment with cone. $$HNO_3 $$
  • Heating charcoal with steam to make it more porous
  • Adding silica to charcoal
Which of the following curves represents the chemical adsorption? 
List I contains the type of colloid while List ll contains the examples. 
List IList II
A. Sol p. Dust
B. Aerosol q. Cheese
C. Gel  r. Soap lather
D. Foams. Plant cell fluid 
  • A-s B-r C-p D-q
  • A-s B-p C-q D-r
  • A-r B-s C-q D-p
  • A-r B-p C-s D-q
  • A-p B-r C-s D-q
Select the correct statements among the following:
  • Milk is emulsion of fat in water.
  • An emulsifier stabilizes the emulsion
  • Emulsifier forms a thin film around the droplets of dispersed phase
  • Milk is an emulsion of protein in water
Match the Column-I with Column-II. Choose the correct' one from the alternatives (a), (b) , (c) and (d). 

Column - IColumn-II
P. Wilkinson catalyst I. trans -$$IrCl(CO)(PPh_3)_2$$
Q. Speier catalystII. Hydrosilylation 
R. Water gas shift catalyst III. $$RhCl (PPh_3)_3$$
S. Zeolite ZSM-5 catalyst  IV. Synthetic gasoline
V. Hydroformylation
 VI. Zinc-copper oxide
  • (a) P- III (b) P- I (c) P- IV (d) P- III
  • (a) Q- II (b) Q- V (c) Q- II (d) Q- IV
  • (a) R- VII (b) R- III (c) R- VI (d) R- IV
  • (a) S- IV (b) S- IV (c) S- IV (d) S- II
Which type of catalyst is ethanol in the following reaction?

$$CHCl_3+O_2\xrightarrow{{C_2H_5OH}}2COCl_2+2HCl$$.
  • Positive catalyst
  • Negative catalyst
  • Bio-catalyst
  • Autocatalyst
Which of the following represents physical adsorption?
Which of the following statements is incorrect regarding physiosorptions?
  • More easily liquifiable gases are adsorbed readily
  • Under high pressure it results into multi molecular layer on adsorbent surface
  • Enthalpy of adsorption ($$\Delta {H}_{adsorption})$$ is low and positive
  • It occurs because of van der Waal's forces
The volume of gases $$H_2, CH_4, CO_2$$ and $$NH_3$$ adsorbed by 1 g of charcoal at 288 K are in the order:
  • $$CO_2>NH_3>H_2>CH_4$$
  • $$NH_3>CO_2>CH_4>H_2$$
  • $$CO_2>CH_4>NH_3>H_2$$
  • $$CH_4>CO_2>NH_3>H_2$$
Following reaction is catalysed by $$Br^- (aq)$$
$$2 H_2O_2 (aq) \rightarrow 2 H_2O (l) + O_2 (g)$$
This is an example of 
  • homogeneous catalysis
  • heterogeneous catalysis
  • autocatalysis
  • enzyme catalysis
The enthalpy($$H$$) of an elementary exothermic reaction $$A\rightleftharpoons B$$ is schematically plotted against the reaction coordinate. The plots in the presence and absence of a catalyst are shown in dashed and solid lines, respectively. Identify the correct plot for the reaction.
In which one of the following properties, physisorption and chemisorption resemble each other?
  • Force of attraction
  • Enthalpy of adsorption
  • Temperature effect
  • Effect of surface area
  • Number of adsorption layers
Which is correct about physical adsorption?
  • High temperature and high pressure favour adsorption
  • High temperature and low pressure favour adsorption
  • Low temperature and high pressure favour adsorption
  • Low temperature and low pressure favour adsorption
  • Temperature and pressure have no effect on adsorption
Match list I with List II and select the correct answer using the codes given below the  lists:
List IList II
(A) Coagulation(1) Scattering
(B) Lyophilization(2) Washing of precipitates
(C) Peptization(3) Purification of colloids
(D) Tyndall(4) Electrolyte
  • A-4; B-3; C-2; D-1
  • A-2; B-1; C-3; D-4
  • A-3; B-4; C-2; D-1
  • A-4; B-3; C-1; D-1
Gold sol can be prepared by:
  • hydrolysis of gold(III) chloride
  • oxidation of gold by aqua-regia
  • peptization
  • treating gold (III) chloride with metallic zinc
  • reduction of gold (III) chloride with formalin solution
Some medicines are more effective in the colloidal form because of:
  • the charged colloidal particles present in it
  • the large surface area and easy assimilation
  • precipitation of medicine in the blood
  • the stabilisation of medicine in colloidal form
When an excess of a very dilute aqueous solution of KI is added to a very dilute aqueous solution of silver nitrate, the colloidal particles of silver iodide are associated with which of the following Helmholtz double layer?
Which one of the following processes does not involve coagulation?
  • Peptization
  • Formation of delta
  • Purification of drinking water using alum
  • Tanning of leather using tannin
The graph of the effect of catalyst on activation energy is given below. Fill up the blanks $$X$$ and $$Y$$ with appropriate statements.
934495_a87b16d936f74341b94e28e0b8b9dec4.png
  • $$X =$$ energy of activation without catalyst, $$Y =$$ energy of activation with catalyst
  • $$X =$$ path of reaction with catalyst, $$Y =$$ path of reaction without catalyst
  • $$X =$$ energy of activation with catalyst, $$Y =$$ energy of activation without catalyst
  • $$X =$$ energy of endothermic reaction, $$Y =$$ energy of exothermic reaction
Which of the following statements about the catalyst is true?
  • A catalyst makes the reaction feasible by making $$\triangle G$$ more negative
  • A catalyst makes equilibrium constant more favourable for forward reaction
  • A catalyst accelerate rate of reaction by bringing down the activation energy
  • A catalyst always increases the rate of reaction
Select the correct statement.
  • If the critical micelle concentration (CMC) of a soap is $$10^{-3}$$mol/L the $$10^{-4}$$M solution of soap is a colloidal solution.
  • Charge of dispersed phase and dispersion medium in a colloidal solution can be identified by electrodialysis process.
  • Peptization is defined as the process of converting colloidal sol into precipitate by shaking it with dispersion medium in the small amount of electrolyte
  • The emulsion is water in oil (W/O) when some oil soluble dye is added to it and background becomes coloured.
Artificial smoke screens are made by  
  • $$Al_{2}O_{3}$$
  • $$PbO$$
  • $$Na_{2}O$$
  • $$TiO_{2}$$
Which of the following methods is used for sol destruction?
  • Condensation
  • Dialysis
  • Diffusion through animal membrane
  • Addition of an electrolyte
Which of the following options are correct?
  • Micelle formation by soap in aqueous solution is possible at all temperatures.
  • Micelle formation by soap in aqueous solution occurs above a particular concentration.
  • On dilution of soap solution micelles may revert to individual ions.
  • Soap solution behaves as a normal strong electroyte at all concentrations.
An inhibitor is essentially: 
  • a negative catalyst
  • autocatalyst
  • heterogeneous
  • homogeneous catalyst
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