MCQ Questions for Class 12 Engineering Chemistry Surface Chemistry Quiz 2

Which of the following statements does not show correct difference between adsorption and absorption?

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In adsorption, the substance is concentrated only at the surface while in absorption it is uniformly distributed in the bulk
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Adsorption is instantaneous while absorption is a slow process
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A substance can be adsorbed as well as absorbed simultaneously and the process is called sorption
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Only gases are adsorbed while solids and liquids are absorbed

When the temperature is lowered and pressure is raised, the adsorption of a gas on a solid?

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Decreases
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Increases
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Remains unaffected
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Decreases first then increases

Which of the following kinds of catalysis can be explained by the adsorption theory?

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Heterogeneous catalyst
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enzyme catalysis
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homogeneous catalysis
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acid base catalysis

Physisorption involves:

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Ionic bonding
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Covalent bonding
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Vander walls forces
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London forces

Select incorrect statement

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Micelles are macromolecular colloids
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The electrical charge on a colliod particle is indicated by electrophoresis
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Formation of micelles takes place above kraft temperature
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Formation of micelles takes place below CMC

Explanation

Direction ratios of

$\cfrac{x-2}{2}=\cfrac{y+1}{3}=\cfrac{z}{4}$

$(2,3,4)$

Since it is parallel to normal of required plane

Direction ratios wil be integral multiple of

$(2,3,4)$

By options

$(2,3,4)$ is correct answer

Arrange cotton, silk, wool and nylon is decreasing order of their water absorption capacity

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$Nylon>cotton>wool>silk$
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$Nylon>cotton>silk>wool$
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$Wool>cotton>silk>nylon$
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$cotton>wool>silk>nylon$

A substance forms zwitter ion, It can have functional group.

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$- {\text{N}}{{\text{H}}_{\text{2}}}, - {\text{COOH}}$
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$- {\text{N}}{{\text{H}}_2}, - {\text{S}}{{\text{O}}_{\text{3}}}{\text{H}}$
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Both (A) and (B)
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None of these

Explanation

$- N{H_2}, - COOH \to -N{H^ + _3}, - CO{O^ - }$

$- N{H_2}, - S{O_3}H \to - N{H^ + _3}, - S{O^ - _3}$

Which of the following gas absorb to a maximum amount by an activated charcoal?

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$N_2$
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$O_2$
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$Cl_3$
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$CO_2$

Explanation

$N_{2}$

$N_{2}$ will be strongly absorbed by charcoal because of more surface area and can be easily liquified.

Adsorption played an important role in:

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heterogeneous catalysis
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homogeneous catalysis
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positive catalysis
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negative catalysis

The catalyst used in the reduction of perisulphate to sulphate with iodide ion is

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$Fe^{3+}$
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$Fe^{2+}$
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Both 1 and 2
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$Cr^{2+}$

The charcoal maintained at

$100^oC$ adsorbs

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$Ne$ and $Kr$
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$He$ and $Ar$
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$Ar, Kr$ and $Xe$
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$He$ and $Ne$

Explanation

Except

$He$ , all other noble gases are adsorbed by coconut charcoal at low temperatures. The extent of adsorption increases as the atomic size of the noble gas increases. As the temperature increases the extent of adsorption decreases.

Colloidal solutions of metals like gold, silver and platinum generally prepared by using

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Peptization
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Bredig's arc method
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Exchange of solvent
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Oxidation method

Adsorption is phenomenon in which a substance

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Goes into the body of the other substance
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Remains close the other substance
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Accumulates on the surface of the other substance
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None of these

Which of the following substances can be compressed?

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Sponge
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Stone
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Magnet
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Diamond

Cow milk, an example of neutral emulsion is stabilized by:

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fat
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water
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casein
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${ Mg }^{ 2+ }$ ions

Explanation

Cow milk an example of a neutral emulsion is stabilized by casein.

Cow milk is liquid fat particles dispersed in water. It is oil in water type emulsion. Casein is protective colloid with gold number

$0.01-0.02$ .

Casein is a phosphoprotein which occurs in the milk of mammals as a suspension of calcium caseinate. It is the main protein of milk.

Hence, option C is correct.

Which of the following statements is incorrect regarding physisorption?

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It occurs because of van der Waals forces.
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More easily liquefiable gases are adsorbed readily.
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Enthalpy of adsorption (adsorption) is low and positive.
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Under high pressure it results into multimolecular layer on adsorbent surface.

The following information is available for the reaction:

$R \rightarrow P$

$R \rightarrow P; rate = r_{1}$

$R \overset{A}\rightarrow P; rate = r_{2}$

$R \overset{B}\rightarrow P; rate = r_{3}$

$R \overset{C}\rightarrow P; rate = r_{4}$

$R \overset{D}\rightarrow P; rate = r_{5}$

$R \overset{A + C}\rightarrow P; rate = r_{6}$

$R \overset{A+ D}\rightarrow P; rate = r_{7}$
If

$r_{3} < r_{1} = r_{4} = r_{5} < r_{7} < r_{2} < r_{6}$ , then the only incorrect statement is

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B is an inhibitor.
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C is a catalytic promoter of catalyst A.
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D is a catalytic poison of catalyst A.
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A is a catalytic promoter of catalyst C.

Which metal sol (dispersion medium being water) cannot be prepared by Bredig's are method?

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$K$
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$Cu$
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$Au$
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$Pt$

Which of the following reaction is not used in the preparation of colloidal solution?

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$2H_{2}S + SO_{2} \rightarrow 3S + 2H_{2}O$
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$2Mg + CO_{2} \rightarrow 2MgO + C$
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$FeCl_{3} + 3H_{2}O \rightarrow Fe(OH)_{3} + 3HCl$
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$2AuCl_{3} + 3SnCl_{2} \rightarrow 2Au + 3SnCl_{4}$

Select the correct statement(s)

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If the critical micelle concentration (CMC) of a soap is $10^{-3} M$ , then $10^{-4} M$ solution of this soap will have colloidal nature.
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Charge on the colloidal particles may be determined with the help of dialysis.
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Peptization is the process of conversion of a colloidal sol into precipitate by adding some electrolyte.
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When some oil-soluble dye is added in the water in oil emulsion, the background becomes colored.

The main function of a catalyst in speeding up a reaction is

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To increase the rate of the forward reaction
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To change the reaction path so as to decrease the energy of activation for the reaction
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To reduce the temperature at which the reaction can occur
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To increase the energy of the molecules of the reactants

A catalyst increases the rate of a chemical reaction by_________

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increasing the activation energy
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decreasing the activation energy
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reacting with reactants
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reacting with products

Oil soluble dye is mixed with water in oil emulsion. Then

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dispersion medium is coloured
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different phase is coloured
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both coloured
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none is coloured

Which of the following ion forms primary electrical double layer on the colloidal particle of

$As_{2}S_{3}$ ?

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$As^{3-}$
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$S^{2-}$
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$H^{+}$
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$OH^{-}$

In the adsorption of acetic acid on activated charcoal the acetic acid is an

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Adsorber
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Absorber
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Adsorbent
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Adsorbate

In emulsions, the dispersion medium and dispersed phase are

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Both solids
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Both gases
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Both liquids
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One is solid and other is liquid

When the temperature is lowered and pressure is raised the adsorption of a gas on solid

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decreases
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increases
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remains unaffected
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decreases first then increases

$\underset{Sucrose}{{C_{12}H_{22}O_{11}}+H_{2}O}+H_{2}O\overset{dil.\ H_{2}SO_{4}}{\longrightarrow}\underset{Fructose}{C_{6}H_{12}O_{6}(aq)}+\underset{Glucose}{C_{6}H_{12}O_{6}(aq)}$

In this reaction, dilute

$H_{2}SO_{4}$ is called

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Homogeneous catalysis
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Homogeneous catalyst
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Homogeneous catalysis
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Homogeneous catalyst

Explanation

In this reaction, dilute

$H_{2}SO_{4}$ is called homogeneous catalyst because reactant and catalyst are present in the same physical state i.e. aqueous phase and the reaction is called homogeneous catalysis.

Which one of the following statements is correct in a reversible reaction?

A catalyst-

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increases the rate of forward reaction
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decreases the rate of forward reaction
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increases the rate of backward and forward reactions
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alters the equilibrium constant of the reaction

Which of the following statements is true for a catalyst?

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It increases the energy of the reactants
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It decreases the energy of the products
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It decreases the energy of the reactants
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It does not change the enthalpy of the reactants

Which of the following catalyses the conversion of glucose into ethanol?

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Zymase
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Invertase
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Maltase
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Diastase

Explanation

Zymase is the enzyme complex that catalyses the fermentation of sugar into ethanol and carbon dioxide. It occurs naturally in yeasts.

$\underset{Glucose}{C_{6}H_{12}O_{6}}\xrightarrow[enzyme]{Zymase}\underset{Ethanol}{2C_{2}H_{5}OH}+2CO_{2}$

An emulsion is a colloidal dispersion of

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A liquid in a gas
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A liquid in a liquid
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A solid in a liquid
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A gas in a solid

Amongst the following chemical reactions, the one representing homogeneous catalysis is

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$N_{2}(g)+3H_{2}(g)\overset{Fe}{\rightarrow}2NH_{3}(g)$
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$2SO_{2}(g)+O_{2}(g)\overset{2NO}{\longrightarrow}2SO_{3}(g)+2NO(g)$
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$CO(g)+3H_{2}(g)\overset{Ni}{\rightarrow}CH_{4}(g)+{H_{2}O}$
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$2SO_{2}(g)+O_{2}(g)\overset{V_{2}O_{5}}{\rightarrow}2SO_{3}(g)$

Explanation

$2SO_{2}(g)+O_{2}(g)\overset{2NO}{\longrightarrow}2SO_{3}(g)+2NO(g),$ reaction mixture and catalyst are present in the same gas phase.

Which one of the following changes when catalyst is used in a reaction?

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Heat of reaction
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Product of reaction
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Equilibrium constant
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Activation energy

In the titration between oxalic acid and acidified potassium permanganate, the manganous salt formed catalyzes the reaction. The manganous salt is

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A promoter
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A positive catalyst
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An autocatalyst
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None of these

Platinized asbestos is used as a catalyst in the manufacture of

$H_{2}SO_{4}$ . It is an example of

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Heterogeneous catalyst
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Autocatalyst
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Heterogeneous catalyst
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Induced catalyst

Explanation

$\underset{(g)}{2SO_{2}}+ \underset{(g)}{O_{2}}\xrightarrow[Asbestos]{Platinized}2SO_{3}$ ;

It is an example of heterogenous catalyst as the phase are different.

In the reversible reaction a catalyst is the substance which

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Increases the rate of the forward reaction
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Deceases the value of enthalpy change in the reaction
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Reduces the time required for reaching the equilibrium state in the reaction
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Decreases the rate of the reverse reaction

Catalyst used in hydrogenation of oils is

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Pt
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Mo
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Fe
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Ni

Explanation

$Oil+H_{2}\xrightarrow{{Ni-catalyst}} Ghee$ .

The catalyst used in the hydrogenation of oil is

$Ni.$

Addition of catalyst in a system

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Increases equilibrium concentration
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No effect on equilibrium concentration
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Decreases equilibrium concentation
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Increases rate if forward reaction and decreases rate of backward reaction

The colloidal solution of mercury in water can be easily obtained by

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Mechanical precipitation
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Bredig's arc method
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Repeated washing
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Ultrasonic dispersion

The example of heteropolar sol is:

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Starch sol in water
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Rubber sol in water
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Protein sol in water
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Sulphur sol

A catalyst is substance which

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Increase the equilibrium concentration of the product
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Changes the equilibrium constant of the reaction
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Shortens the time to reach equilibrium
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Supplies energy to the reaction

Platinised asbestos helps in the formation of

$SO_{3}$ , from

$SO_{2}$ and

$O_{2}$ . But, if even a small amount of

$As_{2}O_{3}$ acts here as

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A positive catalyst
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A negative catalyst
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An autocatalyst
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A poison

Explanation

$2SO_{2}+O_{2}\xrightarrow[As_{2}S_{3}(posion)]{Platinised\ asbestos\ (catalyst)}2SO_{3}$

Here even a small amount of

$As_{2}O_{3}$ acts as a poison for the reaction which decreases the yield of the desired product of the reaction.

The decomposition of hydrogen peroxide can be slowed by the addition of a small amount of acetamide. The latter acts as a

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Detainer
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Stopper
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Promoter
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Inhibitor

Which requires catalyst

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$S+O_{2}\rightarrow SO_{2}$
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$2SO_{2}+O_{2}\rightarrow 2SO_{3}$
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$C+O_{2}\rightarrow CO_{2}$
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All

Explanation

$SO_{2}g(g)+O_{2}()\xrightarrow[Asbetos\ (promoter)]{Pt- catalyst }2SO_{3}(g)$

So, option B is correct.

Which one of the following is an incorrect statement for physisorption?

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It is a reversible process
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It requires less heat of adsorption
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It requires activation energy
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It takes place at low temperature

If some gelatin is mixed in collodial solution of gold, then it does

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Coagulation of gold
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Peptization of gold
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Protection of gold sol
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Protection of gelatin

Colloidal solution of arsenious sulphide can be prepared by

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Electrodispersion method
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Peptization
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Double decompositon
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Hydrolysis

Explanation

Arsenious sulphide can be prepared by double decomposition reaction as shown below.

$As_{2}O_{3}+3H_{2}S\rightarrow As_{2}S_{3}+3H_{2}O$

Catalyst used in the oxidation of

$SO_{2}\rightarrow SO_{3}$

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Nickel
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$ZnO.Cr_{2}O_{3}$
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$V_{2}O_{5}$
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Iron

Explanation

$\underset{(g)}{2SO_{2}}+\underset{(g)}{O_{2}}\xrightarrow[catalyst]{V_{2}O_{5}}2SO_{3}$

So, option C is correct.

Physical adsorption is inversely proportional to the_____________

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Volume
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Concentration
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Temperature
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All of these

CBSE Questions for Class 12 Engineering Chemistry Surface Chemistry Quiz 2 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Engineering Chemistry Surface Chemistry Quiz 2 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

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