Advanced Problems in Physical Chemistry for Competitive Examinations

Neeraj Kumar

Chapter 12

Surface Chemistry - all with Video Answers

Educators

JD

Section 1

Exercises I

Problem 1

Which of the following interface can never be obtained?
(a) Liquid-liquid
(b) Solid-solid
(c) Liquid-gas
(d) Gas-gas

Shalini Tyagi

Shalini Tyagi

Numerade Educator

Problem 2

When a chalk stick is dipped in ink, then
(a) the coloured pigments in the ink get absorbed in the chalk.
(b) the solvent get adsorbed at the surface of chalk.
(c) inside of the chalk will remain as white while the surface will have coloured pigments.
(d) inside of the chalk will have coloured pigments while the surface will remain white.

Shalini Tyagi

Numerade Educator

Problem 3

Physical adsorption is appreciable at
(a) Higher temperature
(b) Lower temperature
(c) At room temperature
(d) $100^{\circ} \mathrm{C}$

Shalini Tyagi

Numerade Educator

Problem 4

The rate of chemisorption
(a) decreases with increase of pressure
(b) is independent of pressure
(c) is maximum at one atmospheric pressure
(d) increases with increase of pressure

Shalini Tyagi

Numerade Educator

Problem 5

Chromatography is a technique based on
(a) Solubilities of solute
(b) Adsorption of solute
(c) Chemical adsorption followed by dispersion
(d) Differential adsorption of different constituents of a mixture

JD

Jhamku Devi

Numerade Educator

Problem 6

Which of the following is not a characteristic of chemisorption?
(a) Adsorption is irreversible.
(b) Adsorption decreases with increase in temperature.
(c) Adsorption is specific.
(d) Adsorption increases with increase of surface area.

JD

Jhamku Devi

Numerade Educator

Problem 7

Which one of the following is not a correct statement?
(a) Physical adsorption is reversible in nature.
(b) Physical adsorption involves Vander Waal's forces.
(c) Rate of physical adsorption increases with increase of pressure on the adsorbate.
(d) High activation energy is involved in physical adsorption.

Shalini Tyagi

Numerade Educator

Problem 8

Which gas will be adsorbed on a solid to greater extent?
(a) A gas having non-polar molecules.
(b) A gas having higher critical temperature.
(c) A gas having lowest critical temperature.
(d) A gas having higher critical pressure.

Shalini Tyagi

Numerade Educator

Problem 9

The nature of bonding forces in adsorption is
(a) purely physical like Vander Waal's force
(b) purely chemical
(c) both, physical and chemical, always
(d) none of these

JD

Jhamku Devi

Numerade Educator

Problem 10

Which one of the following is not applicable to chemisorption?
(a) High magnitude of $\Delta H$
(b) Occurs at higher temperature
(c) It is reversible
(d) It forms mono layer

Shalini Tyagi

Numerade Educator

Problem 11

Which characteristic of adsorption is wrong?
(a) Physical adsorption decreases with increase in temperature.
(b) Physical adsorption increases with increase in temperature.
(c) Physical adsorption is a reversible process.
(d) Adsorption is limited only to the surface.

Shalini Tyagi

Numerade Educator

Problem 12

Sorption is the term used when
(a) only adsorption takes place
(b) only absorption takes place
(c) adsorption and absorption occur simultaneously
(d) desorption takes place

Shalini Tyagi

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Problem 13

The volumes of gases $\mathrm{H}_{2}, \mathrm{CH}_{4}, \mathrm{CO}_{2}$ and $\mathrm{NH}_{3}$ adsorbed by $1 \mathrm{~g}$ of charcoal at $288 \mathrm{~K}$ are in the order
(a) $\mathrm{H}_{2}>\mathrm{CH}_{4}>\mathrm{CO}_{2}>\mathrm{NH}_{3}$
(b) $\mathrm{CH}_{4}>\mathrm{CO}_{2}>\mathrm{NH}_{3}>\mathrm{H}_{2}$
(c) $\mathrm{CO}_{2}>\mathrm{NH}_{3}>\mathrm{H}_{2}>\mathrm{CH}_{4}$
(d) $\mathrm{NH}_{3}>\mathrm{CO}_{2}>\mathrm{CH}_{4}>\mathrm{H}_{2}$

JD

Jhamku Devi

Numerade Educator

Problem 14

Which plot is the adsorption isobar for chemisorption?
(a)
(b)
(c)
(d)

JD

Jhamku Devi

Numerade Educator

Problem 15

In the Freundlich adsorption isotherm, the slope of the straight line graph between $\log (x / m)$ and $\log P$ for the adsorption of a gas on solid is
(a) $k$
(b) $\log k$
(c) $n$
(d) $1 / n$

Shalini Tyagi

Numerade Educator

Problem 16

Which one of the following characteristics is not correct for physical adsorption of a gas on solid?
(a) Adsorption is reversible.
(b) Adsorption increase with increase in temperature.
(c) Absorption is spontaneous
(d) Both enthalpy and entropy of adsorption are negative.

Shalini Tyagi

Numerade Educator

Problem 17

The enthalpy of adsorption in physisorption lies in the range
(a) $-(40-400) \mathrm{kJ} / \mathrm{mol}$
(b) $-(80-240) \mathrm{kJ} / \mathrm{mol}$
(c) $-(20-40) \mathrm{kJ} / \mathrm{mol}$
(d) $-(1-10) \mathrm{kJ} / \mathrm{mol}$

Shalini Tyagi

Numerade Educator

Problem 18

In physical adsorption, the forces associated are
(a) Ionic bond
(b) Covalent bond
(c) Vander Waal's forces
(d) All of these

Shalini Tyagi

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Problem 19

How many layers are adsorbed in chemical adsorption?
(a) 1
(b) 2
(c) 3
(d) 1 or more

Shalini Tyagi

Numerade Educator

Problem 20

Rate of physisorption increases with
(a) decrease in temperature
(b) increase in temperature
(c) decrease in pressure
(d) decrease in surface area

Vishal Sharma

Numerade Educator

Problem 21

Which one of the following is not the example of homogeneous catalysis?
(a) Formation of $\mathrm{SO}_{3}$ in the chamber process
(b) Formation of $\mathrm{SO}_{3}$ in the contact process
(c) Hydrolysis of an ester in presence of acid
(d) Decomposition of $\mathrm{KClO}_{3}$ in the presence of $\mathrm{MnO}_{2}$

Shalini Tyagi

Numerade Educator

Problem 22

The decomposition of hydrogen peroxide can be slowed down by addition of a small amount of acetamide. The latter act as
(a) Inhibitor
(b) Promoter
(c) Moderator
(d) Poison

Shalini Tyagi

Numerade Educator

Problem 23

Efficiency of the catalyst depends on its
(a) Molecular mass
(b) Number of free valencies
(c) Physical state
(d) Amount used

Shalini Tyagi

Numerade Educator

Problem 24

Which of the following types of metals make the most efficient catalysts?
(a) Transition metals
(b) Alkali metals
(c) Alkaline earth metals
(d) Radioactive metals

Shalini Tyagi

Numerade Educator

Problem 25

In the reaction: $\mathrm{KMnO}_{4}+\mathrm{H}_{2} \mathrm{SO}_{4}$
$+\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4} \rightarrow$ products, $\mathrm{Mn}^{++}$ ions act as
(a) Positive catalyst
(b) Negative catalyst
(c) Auto catalyst
(d) Enzyme catalyst

Shalini Tyagi

Numerade Educator

Problem 26

In the Haber process of synthesis of $\mathrm{NH}_{3}$
(a) Mo acts as a catalyst and $\mathrm{Fe}$ as a promoter
(b) Fe acts as a catalyst and Mo as a promoter
(c) Feacts as inhibitor and Mo as a catalyst
(d) Fe acts as promoter and Mo as autocatalyst

Shalini Tyagi

Numerade Educator

Problem 27

TEL minimizes the knocking effect when mixed with petrol. It acts as
(a) Positive catalyst
(b) Negative catalyst
(c) Auto-catalyst
(d) Induced catalyst

Shalini Tyagi

Numerade Educator

Problem 28

Platinized asbestos is used as a catalyst in the manufacture of $\mathrm{H}_{2} \mathrm{SO}_{4}$. It is an example of
(a) Homogeneous catalyst
(b) Heterogeneous catalyst
(c) Auto-catalyst
(d) Induced catalyst

Shalini Tyagi

Numerade Educator

Problem 29

The catalyst used in the manufacture of hydrogen by Bosch's process is
(a) $\mathrm{Fe}_{2} \mathrm{O}_{3}$
(b) $\mathrm{Cr}_{2} \mathrm{O}_{3}$
(c) $\mathrm{Fe}_{2} \mathrm{O}_{3}+\mathrm{Cr}_{2} \mathrm{O}_{3}$
(d) $\mathrm{Cu}$

JD

Jhamku Devi

Numerade Educator

Problem 30

In the Ostwald's process for the manufacture of $\mathrm{HNO}_{3}$, the catalyst used is
(a) $\mathrm{Fe}$
(b) $\mathrm{Pt}$
(c) $\mathrm{V}_{2} \mathrm{O}_{5}$
(d) Mo

Hast Aggarwal

Numerade Educator

Problem 31

In a reversible reaction, a catalyst
(a) increases the rate of forward reaction only
(b) increases the rate of forward reaction to a greater extent that of the backward reaction
(c) increases the rate of forward reaction and decreases that of the backward reaction
(d) increases the rate of forward and backward reaction by the same factor.

Shalini Tyagi

Numerade Educator

Problem 32

The decomposition of $\mathrm{H}_{2} \mathrm{O}_{2}$ may be checked by adding a small quantity of phosphoric acid. It is an example of
(a) Neutralization
(b) Negative catalysis
(c) Positive catalysis
(d) Catalytic poisoning

Shalini Tyagi

Numerade Educator

Problem 33

In the manufacture of $\mathrm{H}_{2} \mathrm{SO}_{4}$ by contact process, the presence of $\mathrm{As}_{2} \mathrm{O}_{3}$ acts as
(a) Catalytic promoter
(b) Catalytic poison
(c) Induced catalyst
(d) Auto catalyst

Shalini Tyagi

Numerade Educator

Problem 34

Air can oxidize sodium sulphate in aqueous solution but cannot do so in the case of sodium arsenite. If, however, air is passed through a solution containing both sodium sulphite and sodium arsenite then both are oxidized. This is an example of
(a) Positive catalysis
(b) Negative catalysis
(c) Induced catalysis
(d) Auto catalysis

Shalini Tyagi

Numerade Educator

Problem 35

A catalyst is a substance which
(a) increases the equilibrium concentration of the product.
(b) changes the equilibrium constant of the reaction.
(c) shortens the time to reach equilibrium.
(d) supplies energy to the reaction.

Ishu Khandelwal

Ishu Khandelwal

Numerade Educator

Problem 36

A catalyst
(a) Increases the free energy change in the reaction.
(b) Decrease the free energy change in the reaction.
(c) Does not increase and decreases the free energy change in the reaction.
(d) Can either decrease or increase the free energy change depending on what catalyst we use.

Shalini Tyagi

Numerade Educator

Problem 37

The work of enzymes in living system is
(a) oxygen transfer
(b) to provide immunity
(c) to catalyse biochemical reactions
(d) to provide energy

Shalini Tyagi

Numerade Educator

Problem 38

Which is not correct for heterogeneous catalysis?
(a) The catalyst decreases the energy of activation.
(b) The surface of catalyst plays an important role.
(c) The catalyst forms an intermediate with the reactants, at the surface.
(d) There is no change in the energy of activation.

Shalini Tyagi

Numerade Educator

Problem 39

In the case of auto catalysis
(a) reactant catalyses
(b) heat produced in the reaction catalyses
(c) product catalyses
(d) solvent catalyses

Ishu Khandelwal

Ishu Khandelwal

Numerade Educator

Problem 40

Zeolites are used as catalyst in
(a) Petrochemical industries during cracking
(b) In the preparation of $\mathrm{H}_{2} \mathrm{SO}_{4}$
(c) In the hydrolysis of ester
(d) All

Shalini Tyagi

Numerade Educator

Problem 41

Butter is a colloid formed when
(a) liquid fat is dispersed in liquid fat
(b) liquid fat is dispersed in water
(c) water is dispersed in liquid fat
(d) solid fat is dispersed in water

Shalini Tyagi

Numerade Educator

Problem 42

Lyophobic colloids are
(a) Reversible
(b) Irreversible
(c) Water loving
(d) Solvent loving

Shalini Tyagi

Numerade Educator

Problem 43

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

Shalini Tyagi

Numerade Educator

Problem 44

When freshly precipitated $\mathrm{Fe}(\mathrm{OH})_{3}$ is boiled with water in the presence of few drops of dil. HCl, a hydrated ferric oxide sol is obtained. The method is termed as
(a) Electro dispersion
(b) Peptization
(c) Ultra filtration
(d) Dialysis

Shalini Tyagi

Numerade Educator

Problem 45

Bleeding is stopped by application of ferric chloride. This is because
(a) the blood starts flowing in opposite direction.
(b) the ferric chloride seals the blood vessel.
(c) the blood reacts and forms a solid which seals the blood vessel.
(d) the blood is coagulated and thus, the blood vessel is sealed.

Shalini Tyagi

Numerade Educator

Problem 46

$\mathrm{Fe}^{3+}$ ions coagulate blood. This shows that blood contains colloidal particles bearing
(a) negative charge
(b) positive charge
(c) no charge
(d) either positive or negative charge

Shalini Tyagi

Numerade Educator

Problem 47

Gold number is a measure of
(a) the amount of gold present in the colloidal solution.
(b) the amount of gold required to break the colloid.
(c) the amount of gold required to protect the colloid.
(d) the protective power of lyophilic colloid.

Shalini Tyagi

Numerade Educator

Problem 48

On addition of one $\mathrm{ml}$ solution of $10 \%$ $\mathrm{NaCl}$ to $10 \mathrm{ml}$ red gold sol in the presence of $0.0025 \mathrm{~g}$ of starch, the coagulation is just prevented. The gold number of starch is
(a) 25
(b) $2.5$
(c) $0.25$
(d) $0.025$

Shalini Tyagi

Numerade Educator

Problem 49

All colloidal solution shows
(a) Very high osmotic pressure
(b) High osmotic pressure
(c) Low osmotic pressure
(d) No osmotic pressure

Shalini Tyagi

Numerade Educator

Problem 50

The gold numbers of $\mathrm{A}, \mathrm{B}, \mathrm{C}$ and $\mathrm{D}$ are $0.04,0.002,10$ and 25, respectively. The protective powers of $\mathrm{A}, \mathrm{B}, \mathrm{C}$ and $\mathrm{D}$, respectively, are in the order
(a) $\mathrm{A}>\mathrm{B}>\mathrm{C}>\mathrm{D}$
(b) $\mathrm{B}>\mathrm{A}>\mathrm{C}>\mathrm{D}$
(c) $\mathrm{D}>\mathrm{C}>\mathrm{B}>\mathrm{A}$
(d) $\mathrm{C}>\mathrm{A}>\mathrm{B}>\mathrm{D}$

Shalini Tyagi

Numerade Educator

Problem 51

The charge of $\mathrm{As}_{2} \mathrm{~S}_{3}$ sol is due to the absorbed
(a) $\mathrm{H}^{+}$
(b) $\mathrm{OH}$
(c) $\mathrm{O}^{2}$
(d) $\mathrm{S}^{2}$

Shalini Tyagi

Numerade Educator

Problem 52

The movement of dispersion medium in an electric field when the dispersed particles are prevented from moving is called
(a) Cataphoresis
(b) Electrophoresis
(c) Electro-osmosis
(d) Brownian movement

Shalini Tyagi

Numerade Educator

Problem 53

To coagulate gelatin sol, which of the following is most effective?
(a) $\mathrm{NaCl}$
(b) $\mathrm{Na}_{3} \mathrm{PO}_{4}$
(c) $\mathrm{AlCl}_{3}$
(d) Alcohol

Shalini Tyagi

Numerade Educator

Problem 54

The potential difference between the fixed charged layer and the diffused layer having opposite charge is called
(a) Colloidal potential
(b) Zeta potential
(c) Electrostatic potential
(d) Electrode potential

Shalini Tyagi

Numerade Educator

Problem 55

An examples of micelle is
(a) $\mathrm{As}_{2} \mathrm{O}_{3}$ solution
(b) Ruby glass
(c) $\mathrm{Na}_{2} \mathrm{CO}_{3}$ solution
(d) Concentrated sodium stearate solution

Shalini Tyagi

Numerade Educator

Problem 56

A freshly prepared $\mathrm{Fe}(\mathrm{OH})_{3}$ precipitate is peptized by adding $\mathrm{FeCl}_{3}$ solution. The charge on the colloidal particle is due to preferential absorption of
(a) $\mathrm{Cl}$ ions
(b) $\mathrm{Fe}^{\text {th }}$ ions
(c) $\mathrm{OH}^{-}$ ions
(d) $\mathrm{H}^{+}$ ions

Shalini Tyagi

Numerade Educator

Problem 57

Hardy-Schulze rule state that
(a) Non-electrolytes have better coagulating action on colloids than electrolytes.
(b) Sols are coagulated by effective ions whose charge is opposite to that of sol and the ions of higher charge are much more effective than the ions of lower charge.
(c) Charge of the ions has no effect on the coagulation of a sol.
(d) Sols are coagulated only by those ions whose charge is similar to that of the sol.

Shalini Tyagi

Numerade Educator

Problem 58

Among the following, which is the correct statement about milk?
(a) Milk is an emulsion of liquid fat in water
(b) Milk in emulsion of protein in water
(c) Milk is stabilized by protein
(d) Milk is stabilized by fat

Akhil Choudhary

Akhil Choudhary

Numerade Educator

Problem 59

Colloidal particles carry charge. This can be shown by
(a) Tyndall effect
(b) Electrophoresis
(c) Brownian movement
(d) Dialysis

Shalini Tyagi

Numerade Educator

Problem 60

Which of the following is most effective in causing the coagulation of ferric hydroxide sol?
(a) $\mathrm{KCl}$
(b) $\mathrm{K} \mathrm{NO}_{3}$
(c) $\mathrm{K}_{2} \mathrm{SO}_{4}$
(d) $\mathrm{K}_{3} \mathrm{Fe}(\mathrm{CN})_{6}$

Shalini Tyagi

Numerade Educator

Problem 61

On adding $\mathrm{AgNO}_{3}$ solution into $\mathrm{KI}$ solution, a negatively charged colloidal sol is obtained when they are in
(a) $100 \mathrm{ml}$ of $0.1 \mathrm{M} \mathrm{AgNO}_{3}+100 \mathrm{ml}$ of
$0.1 \mathrm{M} \mathrm{KI}$
(b) $100 \mathrm{ml}$ of $0.1 \mathrm{M} \mathrm{AgNO}_{3}+50 \mathrm{ml}$ of
$0.2 \mathrm{M} \mathrm{KI}$
(c) $100 \mathrm{ml}$ of $0.1 \mathrm{M} \mathrm{AgNO}_{3}+50 \mathrm{ml}$ of
$0.1 \mathrm{M} \mathrm{KI}$
(d) $100 \mathrm{ml}$ of $0.1 \mathrm{M} \mathrm{AgNO}_{3}+100 \mathrm{ml}$ of
$0.15 \mathrm{M} \mathrm{KI}$

Akhil Choudhary

Akhil Choudhary

Numerade Educator

Problem 62

Substances whose solutions can readily diffuse through animal membranes are called
(a) Colloids
(b) Crystalloids
(c) Electrolytes
(d) Non-clectrolytes

Shalini Tyagi

Numerade Educator

Problem 63

The size of the colloidal particles is in between
(a) $10^{-7}$ and $10^{-9} \mathrm{~cm}$
(b) $10^{-9}$ and $10^{-11} \mathrm{~cm}$
(c) $10^{-4}$ and $10^{-7} \mathrm{~cm}$
(d) $10^{-2}$ and $10^{-3} \mathrm{~cm}$

Shalini Tyagi

Numerade Educator

Problem 64

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

Ishu Khandelwal

Ishu Khandelwal

Numerade Educator

Problem 65

An emulsion is a colloidal solution consisting of
(a) two solids
(b) two liquids
(c) two gases
(d) one solid and one liquid

Shalini Tyagi

Numerade Educator

Problem 66

Peptization is a process of
(a) precipitating the colloidal particles.
(b) purifying the colloidal sol.
(c) dispersing the precipitate into colloidal sol.
(d) movement of colloidal particles towards the opposite charged electrodes.

Shalini Tyagi

Numerade Educator

Problem 67

Colloids are purified by
(a) Brownian motion
(b) Precipitation
(c) Dialysis
(d) Filtration

Shalini Tyagi

Numerade Educator

Problem 68

Which of the following substance give a positively charged sol?
(a) Gold
(b) Arsenious sulphide
(c) Starch
(d) Ferric hydroxide

Akhil Choudhary

Akhil Choudhary

Numerade Educator

Problem 69

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

Akhil Choudhary

Akhil Choudhary

Numerade Educator

Problem 70

Tanning of leather is
(a) colouring of leather by chemicals.
(b) drying process to make the leather hard.
(c) polishing of leather to make it look attractive.
(d) coagulative hardening of the leather by chemicals.

Akhil Choudhary

Akhil Choudhary

Numerade Educator

Problem 71

Surface tension of lyophilic sol is
(a) lower than that of dispersion medium
(b) more than that of dispersion medium
(c) equal than that of dispersion medium
(d) any of these, depending on the dispersion medium

Akhil Choudhary

Akhil Choudhary

Numerade Educator

Problem 72

Which forms a colloidal solution in water?
(a) $\mathrm{NaCl}$
(b) Glucose
(c) Starch
(d) Barium nitrate

Shalini Tyagi

Numerade Educator

Problem 73

When dilute aqueous solution of $\mathrm{AgNO}_{3}$ (excess) is added to KI solution, positively charged sol particles of $\mathrm{AgI}$ are formed due to adsorption of ion
(a) $\mathrm{K}^{+}$
(b) $\mathrm{Ag}^{+}$
(c) I
(d) $\mathrm{NO}_{3}$

Shalini Tyagi

Numerade Educator

Problem 74

Which one of the following substances is not used for preparing lyophilic sols?
(a) Metal sulphide
(b) Gum
(c) Gelatin
(d) Starch

Shalini Tyagi

Numerade Educator

Problem 75

Which of the following is not a colloidal system?
(a) Sugar in water
(b) Muddy water
(c) Concrete
(d) Bread

Shalini Tyagi

Numerade Educator

Problem 76

Tyndall effect in colloidal solution is due to
(a) absorption of light
(b) scattering of light
(c) reflection of light
(d) presence of electrically charged particles

Shalini Tyagi

Numerade Educator

Problem 77

Which of the following substances will have least CMC value?
(a) $\mathrm{C}_{6} \mathrm{H}_{13} \mathrm{COOK}$
(b) $\mathrm{C}_{9} \mathrm{H}_{19} \mathrm{SO}_{3} \mathrm{Na}$
(c) $\mathrm{C}_{11} \mathrm{H}_{22} \mathrm{NH}_{4} \mathrm{Cl}$
(d) $\mathrm{C}_{8} \mathrm{H}_{17} \mathrm{COONa}$

Shalini Tyagi

Numerade Educator

Problem 78

In the styrene foam, the dispersed phase and dispersion medium are, respectively,
(a) gas, gas
(b) gas, solid
(c) solid, solid
(d) liquid, solid

Shalini Tyagi

Numerade Educator

Problem 79

What happens when a lyophilic sol is added to a lyophobic sol?
(a) Lyophilic sol gets protected by the lyophobic sol.
(b) Lyophobic sol is coagulated.
(c) Lyophilic sol is coagulated.
(d) Lyophobic sol is protected by the lyophobic sol.

Akhil Choudhary

Akhil Choudhary

Numerade Educator

Problem 80

Lyophilic sols are more stable than lyophobic sols because
(a) the colloidal particles have positive charge.
(b) the colloidal particles have no charge.
(c) the colloidal particles are highly solvated.
(d) there are strong electrostatic repulsions between the charged colloidal particles.

Shalini Tyagi

Numerade Educator