Chemistry NCERT Exemplar Solutions Class 12th Chapter Five: Overview, Questions, Preparation

Which of the following process does not occur at the interface of phases?

(i) Crystallisation

(ii) Heterogeneous catalysis

(iii) Homogeneous catalysis

(iv) Corrosion

At the equilibrium position in the process of adsorption  ?

(i) ΔH > 0

(ii) ΔH = TΔS

(iii)  ΔH > TΔS

(iv)  ΔH < TΔS

Which of the following interface cannot be obtained?

(i) Liquid-liquid

(ii) Solid-liquid

(iii)  Liquid-gas

(iv)  Gas-gas.

The term ‘sorption’ stands for .

(i) Absorption

(ii) Adsorption

(iii)  Both absorption and adsorption

(iv)  Desorption

Extent of physisorption of a gas increases with  

(i) Increase in temperature.

(ii) Decrease in temperature.

(iii) Decrease in surface area of adsorbent.

(iv) Decrease in strength of van der waals forces

Extent of adsorption of adsorbate from solution phase increases with

(i) Increase in amount of adsorbate in solution.

(ii) Decrease in surface area of adsorbent.

(iii)  Increase in temperature of solution.

(iv)  Decrease in amount of adsorbate in solution.

Which one of the following is not applicable to the phenomenon of adsorption?

(i) ΔH > 0

(ii) ΔG < 0

(iii)  ΔS < 0

(iv) ΔH < 0

Which of the following is not a favourable condition for physical adsorption?

(i) High pressure

(ii) Negative δh

(iii)  Higher critical temperature of adsorbate

(iv)  High temperature

Physical adsorption of a gaseous species may change to chemical adsorption with

(i) Decrease in temperature

(ii) Increase in temperature

(iii)  Increase in surface area of adsorbent

(iv)  Decrease in surface area of adsorbent.

In physisorption adsorbent does not show specificity for any particular gas because

(i) Involved van der Waals forces are universal.

(ii) Gases involved behave like ideal gases.

(iii)  Enthalpy of adsorption is low.

(iv)  It is a reversible process.

Which of the following is an example of absorption?

(i) Water on silica gel

(ii) Water on calcium chloride

(iii) Hydrogen on finely divided nickel

(iv) Oxygen on metal surface

On the basis of data given below predict which of the following gases shows least adsorption on a definite amount of charcoal?

(i) CO₂

(ii) SO₂

(iii) CH₄

(iv) H₂ 

In which of the following reactions heterogenous catalysis is involved? 

(a) 2SO2( g)+O2( g)+NO(g)→2SO3( g)

(b) 2SO2( g)+Pt(s)→2SO3( g)

(c) N2( g)+3H2( g)+Fe(s)→2NH3( g)

(d) CH3COOCH3(�)+H2O(�)+���(�)→CH3COOH(��)+CH3OH(��)

(i) (b), (c)

(ii) (b), (c), (d)

(iii) (a), (b), (c)

(iv) (d)

At high concentration of soap in water, soap behaves as 

(i) Molecular colloid

(ii) Associated colloid

(iii) Macromolecular colloid

(iv) Lyophilic colloid

Which of the following will show Tyndall effect?

(i) Aqueous solution of soap below critical micelle concentration.

(ii) Aqueous solution of soap above critical micelle concentration.

(iii)  Aqueous solution of sodium chloride.

(iv)  Aqueous solution of sugar.

Method by which lyophobic sol can be protected.

(i) By addition of oppositely charged sol.

(ii) By addition of an electrolyte.

(iii) By addition of lyophilic sol.

(iv) By boiling.

Freshly prepared precipitate sometimes gets converted to colloidal solution by _________.

(i) Coagulation

(ii) Electrolysis

(iii) Diffusion

(iv) Peptisation

Which of the following electrolytes will have maximum coagulating value for AgI/Ag⁺ sol?

(i) Na₂S 

(ii) Na₃PO₄

(iii) Na₂SO₄

(iv) NaCl

A colloidal system having a solid substance as a dispersed phase and a liquid as a dispersion medium is classified as .

(i) Solid sol

(ii) Gel

(iii) Emulsion

(iv)  Sol

The values of colligative properties of colloidal solution are of small order in comparison to those shown by true solutions of same concentration because of colloidal particles  .

(i) Exhibit enormous surface area.

(ii) Remain suspended in the dispersion medium.

(iii)  Form lyophilic colloids.

(iv)  Are comparatively less in number.

Arrange the following diagrams in correct sequence of steps involved in the mechanism of catalysis, in accordance with modern adsorption theory

(i) a →b →c →d →e

(ii) a →c →b →d →e

(iii) a →c →b →e →d

(iv) a →b →c →e →d

Which of the following process is responsible for the formation of delta at a place where rivers meet the sea?

(i) Emulsification

(ii) Colloid formation

(iii) Coagulation

(iv) Peptisation

Which of the following process is not responsible for the presence of electric charge on the sol particles?

(i) Electron capture by sol particles.

(ii) Adsorption of ionic species from solution.

(iii) Formation of Helmholtz electrical double layer.

(iv) Absorption of ionic species from solution.

Which of the following phenomenon is applicable to the process shown in the Fig. 5.1?

(i) Absorption

(ii) Adsorption

(iii) Coagulation

(iv) Emulsification

Which of the following options are correct?

(i) Micelle formation by soap in aqueous solution is possible at all temperatures.

(ii) Micelle formation by soap in aqueous solution occurs above a particular concentration.

(iii) On dilution of soap solution micelles may revert to individual ions.

(iv) Soap solution behaves as a normal strong electrolyte at all concentrations.

Which of the following statements are correct about solid catalyst?

(i) Same reactants may give different product by using different catalysts.

(ii) Catalyst does not change ΔH of reaction.

(iii) Catalyst is required in large quantities to catalyse reactions.

(iv) Catalytic activity of a solid catalyst does not depend upon the strength of chemisorption.

Freundlich adsorption isotherm is given by the expression x/m= kp^1/x which of the following conclusion can be drawn from this expression.

(i) When 1/n= 0, the adsorption is independent of pressure.

(ii) When 1/n= 0, the adsorption is directly proportional to pressure.

(iii) When n= 0, x/m vs p graph is a line parallel to x-axis.

(iv) When n= 0, plot of x/m vs p is a curve.

H₂ gas is adsorbed on activated charcoal to a very little extent in comparison to easily liquefiable gases due to ____________.

(i) Very strong van der Waal’s interaction.

(ii) Very weak van der Waals forces.

(iii) Very low critical temperature.

(iv) Very high critical temperature.

Which of the following statements are correct?

(i) Mixing two oppositely charged sols neutralises their charges and stabilises the colloid.

(ii) Presence of equal and similar charges on colloidal particles provides stability to the colloids.

(iii) Any amount of dispersed liquid can be added to emulsion without destabilising it.

(iv) Brownian movement stabilises sols.

An emulsion cannot be broken by __________ and ___________.

(i) Heating

(ii) Adding more amount of dispersion medium

(iii) Freezing

(iv) Adding emulsifying agent

Which  of the  following substances will  precipitate  the  negatively  charged emulsions?

(i) KCl           

(ii) Glucose                 

(iii)  Urea               

(iv)  NaCl

Which  of the  following colloids  cannot  be  coagulated easily?

(i) Lyophobic colloids.

(ii) Irreversible colloids.

(iii) Reversible  colloids.

(iv) Lyophilic colloids.

What happens when a lyophilic sol is added to a lyophobic sol?

(i) Lyophobic sol is protected.

(ii) Lyophilic sol is protected.

(iii) Film of lyophilic sol is  formed  over  lyophobic sol.

(iv) Film of lyophobic sol is formed  over  lyophilic 

Which phenomenon occurs when an electric field is applied to a colloidal solution and electrophoresis is prevented? 

(i) Reverse osmosis takes place. 

(ii) Electroosmosis takes place. 

(iii) Dispersion medium begins to move.

(iv) Dispersion medium becomes stationary. 

In a reaction, catalyst changes ____________.

(i) Physically

(ii) Qualitatively

(iii) Chemically

(iv) Quantitatively

Which of the following phenomenon occurs when a chalk stick is dipped in ink?

(i) Adsorption of coloured substance

(ii) Adsorption of solvent

(iii) Absorption and adsorption both of solvent

(iv) Absorption of solvent

Method of information of solution is given in Column I. Match it with the type of solution given in Column II

In the following questions a statement of assertion followed by statement of reason is given. Choose the correct answer out of the following choices.

(i) Assertion and reason both are correct and the reason is correct explanation of assertion.

(ii) Assertion and reason both are correct but reason does not explain assertion.

(iii) Assertion is correct but reason is incorrect.

(iv) Both assertion and reason are incorrect.

(v)  Assertion is incorrect but reason is correct.

1. Assertion: An ordinary filter paper impregnated with collodion solution stops the flow of colloidal particles.

Reason: Pore size of the filter paper becomes more than the size of colloidal particle.

Assertion: Colloidal solutions show colligative properties.

Reason: Colloidal particles are large in size. 

Assertion: Colloidal solutions do not show brownian motion.

Reason: Brownian motion is responsible for stability of sols.

Assertion: Coagulation power of Al³⁺ is more than Na⁺.

Reason: Greater the valency of the flocculating ion added, greater is its power to cause precipitation (Hardy Schulze rule).

Assertion: Detergents with low CMC are more economical to use

Reason: Cleansing action of detergents involves the formation of micelles. These are formed when the concentration of detergents becomes equal to CMC.

What is the role of adsorption in froth floatation process used especially for concentration of sulphide ores?

What do you understand by shape selective catalysis? Why are zeolites good shape selective catalysts?

What is collodion?                       

A colloid is formed by adding FeCl₃ in excess of hot water. What will happen if excess sodium chloride is added to this colloid?

On the basis of Hardy-Schulze rule explain why the coagulating power of phosphate is higher than chloride.

Give an example where physisorption changes to chemisorption with rise in temperature. Explain the reason for change.

Geraniol, a volatile organic compound, is a component of rose oil. The density of the vapour is 0.46 gL^-1 at 257°C and 100 mm Hg. The molar mass of geraniol is___________ g mol^-1 (Nearest Integer).

[Given R = 0.082 L atm K^-1 mol^-1]

17.0g of NH₃ completely vapourises at -33.42°C and 1 bar pressure and the enthalpy change the process is 23.4 kJ mol^-1. The enthalpy change for the vapourisation of 85g of NH₃ under the same conditions is_____ kJ.

1.2 mL of acetic acid is dissolved in water to make 2.0L of solution. The depression in freezing point observed for this strength of acid is 0.0198°C. The percentage of dissociation of the acid is_____________. (Nearest Integer).

[Given Density of acetic acid is 1.02g mL^-1

Molar mass of acetic acid is 60g mol^-1]

A dilute solution of sulphuric acid is electrolyzed using a current of 0.10 A for 2 hours to produce hydrogen and oxygen gas. The total volume of gases produced at STP is __________ cm³. (Nearest Integer).

[Given: Faraday constant F = 96500 C mol^-1 at STP, molar volume of an ideal gas is 22.7 L mol^-1]

The activation energy of one of the reactions is a biochemical process is 532611 J mol^-1 when the temperature falls from 310 K to 300 K, the change in rate constant observed is k₃₀₀ = x × 10^-3 k₃₁₀. The value of x is___________.

[Given: In 10 = 2.3 R = 8.3 JK^-1 mol^-1]

The number of terminal oxygen atoms present in the product B obtained from the following reaction is_____________.

$FeC{r}_2{O}_4+N{a}_{2}C{O}_3+O_2\to A+F{e}_2{O}_3+C{O}_2$

$A+H^{+}\to B+H_{2}O+N{a}^{+}$

An acidified magnate solution undergoes disproportionation reaction. The spin- only magnetic moment value of the product having manganese in higher oxidation state is________ B.M. (Nearest Integer)

Kjeldahl’s method was used for the estimation of nitrogen in an organic compound. The ammonia evolved from 0.55g of the compound neutralized 12.5 mL of 1M H₂SO₄ solution. The percentage of nitrogen in the compound is_________ (Nearest Integer)

Observe structure of the following compounds

The total number of structures / compounds which possess asymmetric atoms is________.

Production of iron in blast furnace follows the following equation

$F{e}_3{O}_4\left(s\right)+4CO\left(g\right)\to 3Fe\left(I\right)+4C{O}_2\left(g\right)$

When 4.640 kg of Fe₃O₄ and 2.520 kg of CO are allowed to react then the amount of iron (in g) produced is:

[Given : Molar Atomic mass (g mo^-1); Fe = 56

 Molar Atomic mass (g mol^-1); O = 16

Molar Atomic mass (g mol^-1); C = 12]

Which of the following statements are correct?

           (A) The electronic configuration of Cr is [Ar] 3d⁵4s¹.

           (B) The magnetic quantum number may a negative value.

           (C) In the ground state of an atom, the orbitals are filled in order of their increasing energies.

           (D) The total number of nodes are given by (n-2)

           Choose the most appropriate answer from the options given below:

Arrange the following in the decreasing order of their covalent character:

           (A) LiCl
            (B) NaCl

          (C) KCl

           (D) CsCl

Choose the most appropriate answer from the options given below:

Which of the following is a correct statements?

           (a) Brownian motion destabilizes sols

           (b) Any amount of dispersed phase can be added to emulsion without establishing it.

           (c) Mixing two oppositely charged sols in equal amount neutralizes charges and stabilizes colloids.

           (d) Presence of equal and similar charges on colloidal particles provides stability to the colloidal solution.

Production of iron in blast furnace follows the following equation

$F{e}_3{O}_4\left(s\right)+4CO\left(g\right)\to 3Fe\left(I\right)+4C{O}_2\left(g\right)$

When 4.640 kg of Fe₃O₄ and 2.520 kg of CO are allowed to react then the amount of iron (in g) produced is:

[Given : Molar Atomic mass (g mo^-1); Fe = 56

Molar Atomic mass (g mol^-1); O = 16

Molar Atomic mass (g mol^-1); C = 12]

Which of the following statements are correct?

(A) The electronic configuration of Cr is [Ar] 3d⁵4s¹.

(B) The magnetic quantum number may a negative value.

(C) In the ground state of an atom, the orbitals are filled in order of their increasing energies.

(D) The total number of nodes are given by (n-2)

Arrange the following in the decreasing order of their covalent character:

(A) LiCl
(B) NaCl
(C) KCl
(D) CsCl

In isolation of which one of the following metals from their ores, the use of cyanide salt is not commonly involved?

Which one of the following reactions indicates the reducing ability of hydrogen peroxide in basic medium?

Match List – I with List – II

  List – I                                                                              List – II

(Metal)                                                                            (Emitted light wavelength (nm))

(A) Li                                                                                 (I) 670.8

(B) Na                                                                               (II) 589.2

(C) Rb                                                                               (III) 780.0

(D) Cs                                                                               (IV) 455.5

Choose the most appropriate answer from the options given below:

Match the List – I with List – II

             List – I                                                                               List – II

           (Metal)                                                                            (Application)

           (A) Cs                                                                               (I) High temperature thermometer

           (B) Ga                                                                               (II) Water repellent sprays

           (C) B                                                                                  (III) Photoelectric cells

           (D) Si                                                                                 (IV) Bullet proof vest

           Choose the most appropriate answer from the options given below:

The oxoacid of phosphorus that is easily obtained from a reaction alkali and white phosphorus and has two P-H bonds, is:

Two isomers ‘A’ and ‘B’ with molecular formula C₄H₈ give different products on oxidation with KMnO₄ is acidic medium. Isomer ‘A’ on reaction with KMnO₄/H⁺ results in effervescence of a gas and given ketone. The compound ‘A’ is

 

Given below are two statements:

Statement I: The esterification of carboxylic acid with an alcohol is a nucleophilc acyl substitution.

Statement II: Electron withdrawing groups in the carboxylic acid will increase the rate of esterification reaction

Choose the most appropriate option:

Given below are two statements:

Statement I : Phenols are weakly acidic

Statement II : Therefore they are freely soluble in NaOH solution and are weaker acids than alcohols and water

Choose the most appropriate options:

If a rocket runs on a fuel (C₁₅H₃₀) and liquid oxygen, the weight of oxygen required and CO₂ released for every litre of fuel respectively are :                                                                                                

(Given : density of the fuel is 0.756 g/mL)

Consider the following pairs of electrons

(a) $n=3,\mathcal{l}=1,m_{\mathcal{l}}=1,m_s=+\frac{1}{2}$

(b) $n=3,\mathcal{l}=2,m_{\mathcal{l}}=1,m_s=+\frac{1}{2}$

(a) $n=3,\mathcal{l}=2,m_{\mathcal{l}}=-2,m_s=-\frac{1}{2}$ ${}_{}{}_{}\frac{}{}$

(b) $n=3,\mathcal{l}=2,m_{\mathcal{l}}=-1,m_s=-\frac{1}{2}$

(a) ${}_{}{}_{}\frac{}{}$ $n=4,\mathcal{l}=2,m_{\mathcal{l}}=2,m_s=+\frac{1}{2}$

(b) $n=3,\mathcal{l}=2,m_{\mathcal{l}}=-2,m_s=+\frac{1}{2}$

The pairs of electrons present in degenerate orbitals is/are :

Match List – I with List – II                                                                                               (Chemical Bonding)

List – I                                          List – II

(A)  [PtCl₄]^2-                                 (I)   sp³d

(B)  BrF₅                                       (II)  d²sp³

(C)  PCl₅                                        (III) dsp²

(D)  [Co(NH₃)₆]³⁺                         (iv) sp³d²

Choose the most appropriate answer from the options given below :

For a reaction at equilibrium                                                                                      

$A\left(g\right)?B\left(g\right)+\frac{1}{2}C\left(g\right)$

The relation between dissociation constant (K), degree of dissociation (a) and equilibrium pressure (p) is given by

Given below are two statements :                                                       

Statement I : Emulsions of oil in water are unstable and sometimes they separate into two layers on standing.

Statement II : For stabilization of an emulsion, excess of electrolyte is added. In the light of the above statements, choose the most appropriate answer from the options given below :

Given below are the oxides :                                                                                                                        

Na₂O, As₂O₃, N₂O, NO and Cl₂O₇

Number of amphoteric oxides is :

Match List – I with List – II:                                                                                                                                 

                  List – I                                   List – II

           (A)  Sphalerite                            (I)   FeCO₃

           (B)  Calamine                              (II)  PbS

           (C)  Galena                                  (III) ZnCO₃

           (D)  Siderite                                 (IV) ZnS

           Choose the most appropriate answer from the options given below :

Which of the following statements are correct?                                                                    

(A)  Both LiCl and MgCl₂ are soluble in ethanol

(B)  The oxides Li₂O and MgO combine with excess of oxygen to give superoxide.

(C)  LiF is less soluble in water than other alkali metal fluorides.

(D)  Li₂O is more soluble in water than other alkali metal oxides.

Choose the most appropriate answer from the options given below :

Identify the correct statement from B₂H₆ from those given below :             

(A)  In B₂H₆, all B-H bonds are equivalent

(B)  In B₂H₆, there are four 3-centre 2- electron bonds

(C)  B₂H₆ is a Lewis acid

(D)  B₂H₆ can be synthesized from both BF₃ and NaBH₄.

(E)  B₂H₆ is planar molecule.

Choose the most appropriate answer from the options given below :

In the given reaction sequence, the major product ‘C’ is : :           

$C_8{H}_{10}\underset{H_{2}S{O}_4}{\overset{HN{O}_3}{\to }}A\underset{\Delta }{\overset{B{r}_2}{\to }}B\underset{KOH}{\overset{alcoholic}{\to }}C$

Two statement are given below:

Statement I : The melting point of monocarboxylic acid even number of carbon atoms is higher than that of with odd number of carbon atoms acid immediately below and above it in the series.

Statement II :  The solubility of monocarboxylic acids in water decreases with increases in molar mass.

Choose the most appropriate options

A polysaccharide ‘X’ on boiling with dil H₂SO₄ ate 393 K under 2-3 atm pressure yields ‘Y’. ‘Y’ on treatment with bromine water give gluconic acid. ‘X’ contains b-glycosidic linkages only. Compound ‘X’ is:

During the qualitative analysis of salt with cation y²⁺, addition of a reagent (X) to alkaline solution of the salt gives a bright red precipitate. The reagent (X) and the cation (y²⁺) present represent respectively are:

Atoms of element X from hcp lattice and those of element Y occupy $\frac{}{}$ of its tetrahedral voids. The percentage of element X in the lattice is ________. (Nearest integer)

2O₃(g) $?$ 3O₂(g)

At 300 K, ozone is fifty percent dissociated. The standard free energy change at this temperature and 1 atm pressure is (-)________. J mol^?1. (Nearest integer)

[Given: In 1.35 = 0.3 and R=8.3 J K^-1 mol^-1]

The osmotic pressure of blood is 7.47 bar at 300K. To inject glucose to a patient intravenously, it has to isotonic with blood. The concentration of glucose solution in gL^-1 is __________.

(Molar mass of glucose = 180 g mol^-1 R = 0.083 L bar K^-1 mol^-1) Nearest integer)

The cell potential for the following cell

$Pt\left|H_2\left(g\right)\right|H^{+}\left(aq\right)\left|\right|C{u}^{2+}\left(0.01M\right)|Cu\left(s\right)$

Is 0.576 V at 298 K. The pH of the solution is __________. (Nearest integer)

(Given : $E_{C{u}^{2+}/Cu}^0=0.34Vand\frac{2.303RT}{F}=0.06V$ )

The rate constants for decomposition of acetaldehyde have been measured over the temperature range 700 – 1000 K. The data has been analysed by plotting ln k vs $\frac{10^3}{T}$ graph. The value of activation energy for the reaction is ___________ kJ mol^-1.

(Nearest integer)

(Given : R = 8.31 J K^-1 mol^-1)

In the cobalt-carbonyl complex : [Co₂(CO)₈], number of Co-Co bonds is “X” and terminal CO lignads is “Y”. X + Y = __________.

A 0.166 g sample of an organic compound was digested with conc. H₂SO₄ and then distilled with NaOH. The ammonia gas evolved was passed through 50.0 mL of 0.5 N H₂SO₄. The used acid required 30.0 mL of 0.25 N NaOH for complete neutralization. The mass percentage of nitrogen in the organic compound is ___________.

The major product ‘A’ of the following given reaction has _________ sp² hybridized carbon atoms.

2, 7-Dimethyl 1-2-6- octadiene  A

Major Product