CBSE Questions for Class 12 Engineering Chemistry Surface Chemistry Quiz 1 - MCQExams.com

A particular adsorption process has the following characteristics : (i) It arises due to van der Waals forces and (ii) it is reversible. Identify the correct statement that describes the above adsorption process :
  • Adsorption is monolayer
  • Energy of activation is low
  • Adsorption increases with increase in temperature
  • Enthalpy of adsorption is greater than 100 kJ mol$$^{-1}$$
The most appropriate method of making egg-albumin sol is:
  • Break an egg carefully and transfer the transparent part of the content to 100 mL of 5% w/V saline solution and stir well.
  • Keep the egg in boiling water for 10 minutes. After removing the shell, transfer the white part of the content to 100 mL of 5% w/V saline solution and homogenize with a mechanical shaker.
  • Keep the egg in boiling water for 10 minutes. After removing the shell, transfer the yellow part of the content to 100 mL of 5% w/V saline solution and homogenize with a mechanical shaker
  • Break an egg carefully and transfer only the yellow part of the content to 100 mL of 5% w/V saline solution and stir well.
Peptization is a :
  • process of converting a colloidal solution into precipitate
  • process of converting precipitate into colloidal solution
  • process of converting soluble particles to form colloidal solution
  • process of bringing colloidal molecule into solution
The moles of $$HCl$$ required to neutralise left $$N{H}_{3}$$ solution after adsorption is:
  • $$0.123$$
  • $$0.175$$
  • $$0.145$$
  • $$0.153$$
Mention catalyst in the following reaction:
$$KClO_3 \rightarrow  KCl + O_2$$ 
  • $$MnO_2$$
  • $$FeCl_3$$
  • $$PdCl_2$$
  • $$ZnO/CuO$$
Which is correct in case of heterogeneous catalyst?
  • The catalyst decreases the energy of active ion.
  • The surface of catalyst plays an important role.
  • The catalyst actually forms a compound with reactants.
  • There is no change in the energy of activation.
Substances, which are added to soaps change their properties in order to make them more useful for a particular application, are called ___.
  • fillers
  • absorbant
  • reagent
  • none
A freshly obtained precipitate of $$SnO_2$$ is peptized by little of $$KOH$$ to give a sol. The sol particles may be represented as :
  • $$[SnO_2]K^{+}$$
  • $$[SnP_2]OH^{-}$$
  • $$[SnO_2]Sn^{4+}$$
  • $$[SnO_2]SnO_3^{2-}$$
Milk is an example of :
  • Aquasol
  • True solution
  • Aerosol
  • Emulsion
Which of the following is homogeneous?
  • Milk
  • Paint
  • Shampoo
  • All of the above
The process of passing of a precipitate into colloidal solution on adding an electrolyte is called
  • dialysis
  • peptization
  • electophoresis
  • electro-osmosis
Sorption is the term used when :
  • adsorption takes place
  • absorption takes place
  • both adsorption and absorption take place
  • desorption takes place
Assertion : Physical adsorption of molecules on the surface requires activation energy.
Reason : The bonds of adsorbed molecules are broken.
  • Both Assertion and Reason are correct and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion
  • Assertion is correct but reason is incorrect
  • Assertion is incorrect but reason is correct
  • Both Assertion and Reason are incorrect
Intermediate compound formation theory explains:
  • homogeneous catalysis
  • heterogeneous catalysis
  • both of the above
  • none of the above
There is desorption of physical adsorption when :
  • temperature is increased
  • temperature is decreased
  • pressure is increased
  • concentration is increased
The metal used as a catalyst in the hydrogenation of oils is:
  • sodium
  • nickel
  • mercury
  • manganese
The ______ colloidal dispersions are called emulsions.
  • liquid-liquid
  • solid-solid
  • gas-gas
  • A and C
The adhering of the molecules of gas on the surface of a solid is called _______ _.
  • mixture
  •  adsorption
  • reduction
  • none of these
A catalyst is a substance which:
  • increases the average kinetic energy of reacting molecules
  • alters the reaction mechanism
  • increases the frequency of collisions of reaction species.
  • None of these
Pesticides & insecticides are available in the form of :
  • powders
  • sprays
  • emulsions
  • all of these
On adding dilute $$HCl$$ to chalk piece, $${CO}_{2}$$ is evolved. This is an example of:
  • a hetrogeneous reaction
  • an acid-base reaction
  • an oxidation-reduction reaction
  • catalysed reaction
In the presence of a catalyst, the heat evolved or absorbed during the reaction:
  • increases
  • decreases
  • remains unchanged
  • may increase or decrease
Which of the following is incorrect for physisorption?
  • Reversible
  • Increases with increase in temperature
  • Low heat of adsorption
  • Increases with increase in surface area
Which of the following metals adsorb hydrogen?
  • Zn
  • Pd
  • Pt
  • K
A colloidal sol can be prepared by:
  • breaking the bulky substance into fine particles of colloidal dimensions
  • increasing the size of molecular particles to form larger aggregates.
  • mixing a substance directly with a dispersion medium
  • all of the above
An emulsion is a colloidal solution of:
  • two solids
  • two liquids
  • two gases
  • one solid and liquid
Emulsifying agent is used for:
  • precipitation of am emulsion
  • denaturation of an emulsion
  • stabilization of an emulsion
  • oxidation of an emulsion
The principal emulsifying agent for w/o emulsion is:
  • proteins
  • gum
  • lamp black
  • synthetic soaps
The emulsifying agent used in o/w emulsion is:
  • protein
  • long chain alcohol
  • lampblack
  • heavy metal salts of fatty acids
When soap or detergent dissolves in water, which of the following is true?
  • The polar water soluble ( hydrophilic) head is on the surface of the micelle whereas non polar oil soluble (hydrophobic) tail is in the center of the micelle.
  • The polar water soluble ( hydrophilic) head is in the center of the micelle whereas non polar oil soluble (hydrophobic) tail is on the surface of the micelle.
  • The polar water soluble ( hydrophilic) head is in the center of the micelle.
  • Non polar oil soluble (hydrophobic) tail is on the surface of the micelle.
Which of the following is true when soap or detergent is added to water?
  • The anions of emulsion repel each other hence do not precipitate.
  • The anions of emulsion attract each other hence do not precipitate.
  • The anions of emulsion repel each other hence precipitate.
  • The anions of emulsion attract each other hence precipitate.
Peptisation involves :
  • precipitation of colloidial particles
  • disintegration of colloidal aggregates
  • evaporation of dispersion medium
  • impact of molecules of the dispersion medium on the colloidal particles
The colloidal sol found effective in the treatment of eye disease is:
  • colloidal sulphur
  • colloidal antimony
  • colloidal silver
  • colloidal gold
Physical adsorption is appreciable at: 
  • higher temperature
  • lower temperature
  • room temperature
  • $$100^oC $$
The homogeneous catalysts is shown by:
  • Haber's process, $${ N }_{ 2 }+3{ H }_{ 2 }\xrightarrow [ ]{ Fe } 2{ NH }_{ 3 }$$
  • Ostwald process, $$4{ NH }_{ 3 }+5{ O }_{ 2 }\xrightarrow [ ]{ Pt } 4NO+6{ H }_{ 2 }O$$
  • Contact process, $$\quad 2S{ O }_{ 2 }+{ O }_{ 2 }\xrightarrow [ ]{ V_{2}O_{5}} 2S{ O }_{ 3 }$$
  • $$2{ C }_{ 2 }{ H }_{ 5 }OH\xrightarrow [ ]{ { H }_{ 2 }{ SO }_{ 4 } } { C }_{ 2 }{ H }_{ 5 }-O-{ C }_{ 2 }{ H }_{ 5 }+{ H }_{ 2 }O$$
Platinised asbestos is used as a catalyst in, the manufacture of $$H_2SO_4$$. It is an example of:
  • homogeneous catalyst
  • heterogeneous catalyst
  • autocatalyst
  • induced catalyst
TEL minimises the knocking effect when mixed with petrol. It acts as:
  • positive catalyst
  • negative catalyst
  • autocatalyst
  • induced catalyst
Which one of the following statements is incorrect in the case of heterogeneous catalyst?
  • The catalyst lowers the energy of activation.
  • The catalyst actually forms a compound with the reactant.
  • The surface of the catalyst plays a very important role.
  • There is no change in the energy of activation.
Which of the following acts as a negative catalyst?
  • Lead tetraethyl as antiknock compound
  • Glycerol in decomposition of $$H_2O_2$$
  • Ethanol in the oxidation of chloroform
  • All of the above
A poisonous gas is adsorbed at activated charcoal. The activated charcoal is:
  • absorber
  • adsorbate
  • adsorbent
  • absorbate
Protons accelerate the hydrolysis of esters. This is an example of a/an:
  • promoter
  • homogeneous catalyst
  • acid-base catalyst
  • autocatalyst
Which statement is not correct?
  • Physical adsorption is due to van der Waals forces.
  • Physical adsorption decreases at high temperature and low pressure.
  • Physical adsorption is reversible.
  • Adsorption energy for chemical adsorption is generally lesser than that for physical adsorption.
Which type of phenomenon is used when coloured dye is removed from solution of sugar by charcoal?
  • Absorption
  • Adsorption
  • Both absorption and adsorption
  • None of the above
Which of the following reactions is an example for homogeneous catalysis :
  • $$2H_2O_2(l)\xrightarrow{MnO_2(s)} 2H_2O (l)+O_2(g)$$
  • $$2SO_2(g)+O_2(g)\xrightarrow{V_2O_5(s)} 2SO_3(g)$$
  • $$2CO(g) +O_2(g) \xrightarrow{NO(g)} 2CO_2(g)$$
  • $$H_2(g) +C_2H_4(g) \xrightarrow{Ni(s)} C_2H_6(g)$$
Which of the following statements is NOT TRUE in respect of hydrophilic sols?
  • They are quite stable and are not easily coagulated
  • There is considerable interaction between dispersed phase and dispersion medium (water)
  • The sol particles are hydrated
  • They are very sensitive to coagulation by a small concentration of electrolytes
For the adsorption of a gas on a solid, the plot of log (x/m) versus log P linear with slope equal to:
  • K
  • log k
  • N
  • $$\dfrac { 1 }{ n } $$
In which emulsion coloured droplets are obtained when oil soluble dye is added to it?
  • Cod liver oil
  • Cold cream
  • Hair cream
  • Milk
Which statement is incorrect for a catalyst?
  • It does not affect the equilibrium constant
  • It increases the proportion of products in less time
  • It decreases the activation energy of a reaction
  • It increases the free energy change for the reaction
The graph between log $$\dfrac { X }{ m }$$ v/s log P is straight-line inclined at an angle $$45^o$$ with intercept 0.What will be the rate of adsorption at pressure of 0.4 atm?
  • 0.4
  • 0.6
  • 0.8
  • 0.9
Which of the following catalysis is an example of negative catalysis?
  • $$\displaystyle 2SO_2 + O_2 \overset{V_2O_5}{\longrightarrow} 2SO_3$$
  • $$\displaystyle CHCl_3 + O_2 \overset{alcohol}{\longrightarrow} 2COCl_2 + 2HCl$$
  • $$\displaystyle 2KClO_3 \overset{MnO_2}{\underset{\Delta}{\longrightarrow}} 2KCl + 3O_2$$
  • $$\displaystyle CO + 3H_2 \overset{Ni}{\longrightarrow} CH_4 + H_2O$$
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