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Universal gas constant R = 8.314 J K−1 mol−1

Avagadro constant NA = 6.022 × 1023 mol−1

Planck’s constant h = 6.626 × 10−34 J s

Speed of light ; C = 3 × 108 m s−1

1. The electronic configuration of element that has the endothermic enthalpy change of standard electron

affinity is,

(1) 3s23p4 (2) 2s22p1 (3) 2s22p3 (4) 2s22p2 (5) 3s23p3

2. Maximum in how many quantum number values of an electron in a 3s orbital and an electron in a 3p

orbital of a Cl atom can resemble and differ respectively?

(1) 3, 1 (2) 2, 3 (3) 3, 2 (4) 2, 2 (5) 3, 3

3. IUPAC name of the compound is,

(1) ethyl 2–cyano–4–ethyl–2–formylpent–3–enoate

(2) ethyl 2–cyano–2–formyl–4–methylhex–3–enoate

(3) ethyl–2–cyano–4–methyl–2–oxohex–3–enoate

(4) ethyl–2–cyano–2–formyl–4–methylhex–3–enoate

(5) ethyl 2–formyl–4–methyl–2nitrile–hex–3–enoate

4. Oxidation numbers of Co in both anionic and cationic parts of complex compound

[Co(NH3)6][Co(CN)4(NO2] are respectively,

(1) +2, +3 (2) +3, +1 (3) +3, +3 (4) +2, +2 (5) +3, +2

Instructions:

This paper consists of 12 pages. (Periodic table is also provided)

Answer all the questions.

Use of calculator is not allowed.

Write your index number in the space provided in the answer sheet.

In each of the questions 1 to 50, pick one of the alternatives from (1), (2), (3), (4), (5)

which is correct or most appropriate and mark your response on the answer sheet

with a cross (X) in accordance with the instructions given on the back of the answer

sheet.

CH3 – C = CH –– C – CN

CH2 – CH3 CO2CH2CH3

CHO

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5. Which of the following molecule could be planer?

(1) AB5 non-polar (2) AB3 non-polar (3) AB4 polar

(4) AB5 polar (5) AB6 non-polar

6. At room temperature a given sample of 40 cm3 of gas mixture containing CO(g), CH4(g) and He(g)

was mixed with excess O2(g) and burnt then the resultant gas mixture was cooled down to room

temperature, where 26 cm3 of volume decrease was observed in gas volume. Then the resultant gas

mixture was passed through KOH solution, a further volume decrease of 28 cm3 was observed.

Assuming that no any gas dissolved in water, find the volume percentages of CO(g), CH4(g) and He(g)

in initial mixture.

(1) 50, 20, 30 (2) 50, 30, 20 (3) 20, 50, 30 (4) 20, 30, 50 (5) 40, 10, 50

7. PbCl2 solid is present in a solution having Ag+ ions with the concentration of x mol dm-3. When

temperature is increased gradually AgCl begins to precipitate at one instance. What is the solubility

product value of PbCl2 at that temperature? (At room temperature Ksp(AgCl) = K)

3

3

)1(x

K

3

32)2(

x

K

3

3

2)3(

x

K

3

2)4(

x

K

32

)5(

x

K

8. Which of the following statement is incorrect?

(1) Solubility of alkali earth metal oxides increases down the group.

(2) When K reacts with excess oxygen, KO2 is obtained as the main product

(3) The thermal stability of alkali earth metal bicarbonates is lesser than corresponding alkali metal

bicarbonates as the covalent character of alkali earth metal bicarbonates is higher than that of

respective alkali metal bicarbonates.

(4) All the s-block metal hydrides are ionic compounds.

(5) Melting point of alkali metals is lesser than respective alkali earth metals.

9. A) C6H5OH B) CH3CH2OH C) CH3COOH D) CH3OH E) H2O

Most probable increasing order of electronegativity of O atom in O – H bonds in each of the above

compounds is,

(1) B < D < E < A < C (2) D < B < E < A < C (3) B < D < A < E < C

(4) E < D < B < A < C (5) A < B < D < E < C

10. The following elementary reaction equilibrium is established by taking a certain number of moles of

A(g) at P0 pressure.

2A(g) ⇌ B(g) + C(g)

Forward and reverse rate constants of the above equilibrium are respectively K1 and K2. Hence which

of the following relationship denotes the partial pressure of A(g) correctly?

2

)1(

1

2

0

K

K

P

2

)2(

2

1

0

K

K

P

1

1

2

0

2

2)3(

KK

K

P

2

2)4(

1

2

00

K

K

PP

2

2)5(

1

2

00

K

K

PP

11. The correct increasing order of C – O bond lengths of the following ions/molecules is,

CO32-, COCl2, CO, C2O4

2-, CO2

(1) CO < COCl2< CO2< C2O42-< CO3

2- (2) CO2< COCl2< CO < C2O42-< CO3

2-

(3) CO < CO2< COCl2< CO32-< C2O4

2- (4) CO2< CO < COCl2< CO32-< C2O4

2-

(5) CO< CO2< COCl2< C2O42-< CO3

2-

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12. Correct statement out of the following is,

(1) Bond energy of SF2, SF4 and SF6 increases in the order of SF2 < SF4< SF6

(2) pH of salt solutions of NaClO, NaClO2 and NaClO3 having equal concentration increases in the

order of NaClO3 < NaClO2 < NaClO

(3) Dipole – dipole interaction plays the major role in the variation of boiling point among HCl, HBr

and HI

(4) Ability of involving to hydrolysis among MgCl2, CaCl2 and SrCl2 varies in the order of

MgCl2< CaCl2< SrCl2

(5) Effective nuclear charge felt by the outer shell electron of Li, C and F increases in the order of

F < C < Li

13. In which of the following reaction, the reaction probability decreases with increase of temperature?

(1) (NH4)2Cr2O7(s) → N2(g) + Cr2O3(s) + H2O(g)

(2) BaSO4(s) → Ba2+(aq) + SO42-(aq)

(3) 2SO2(g) + O2(g) → 2SO3(g)

(4) 4HNO3(l) → 4NO2(g) + O2(g) + 2H2O(g)

(5) CaO(s) + 2NH4Cl(aq) → 2NH3(g) + H2O(l) + CaCl2(aq)

14. 100 cm3 of 0.5 mol dm-3 monobasic weak acid HA was shakened well with 100 cm3 of hexane where

an equilibrium was attained at 25 °C. The pH of the equilibrium mixture was, pH = 4. What is the

partition co-efficient of HA between water and hexane at given temperature?

(At 25°C, Ka = 1 x 10-7 mol dm-3 for HA)

(1) 0.5 (2) 4 (3) 0.25 (4) 8 (5) 2

15. In a certain electrolysis process, mass discharging rate (mass of element discharged per unit time) of

an element at anode/ cathode depends,

(A) On magnitude of charge in discharged ion

(B) On electric current

(C) On the surface area of electrode

(D) On the molar mass of discharged element

(E) On the concentration of discharging ion

(1) Only B and D (2) Only A, B and D (3) Only B, D and E

(4) Only B, C and E (5) All of A, B, C, D and E

16. Vessel A contains V volume HCOOH with the concentration of C1 and Vessel B contains V volume

CH3COOH with the concentration of C2. pH of both solutions is same. n mol of NaOH was added to

these two solutions separately to produce buffer solutions. pH of resultant solutions in the vessels A

and B are pH1 and pH2 respectively. Hence which of the following gives pH1 – pH2 correctly?

nVCC

nVCC

22

11log)1( nVCC

nVCC

21

12log)2( nVC

nVC

2

1log)3(

nVCC

nVCC

12

21log)4(

n

VCVC 21log)5(

17. Which of the following statement regarding C6H5NH2 is false?

(1) A substituted amide is formed in the reaction with CH3COCl

(2) A salt is formed in the reaction with excess CH3I

(3) It can act as both nucleophile and electrophile.

(4) A clear solution is obtained in the reaction with dil.HCl solution.

(5) It is more basic than para-nitro aniline.

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K2

Kf

Kr

K1

18. 2A(g) + 2B(g) → C(g) The given reaction takes place via three steps as shown below.

A(g) + B(g) ⇌ Y(g) (fast)

Y(g) + 2B(g) → X(g) (slow)

X(g) + A(g) → C(g) (fast)

Kf and Kr are forward and reverse rate constants of 1st step and K1 and K2 are rate constants of 2nd and

3rd steps respectively. Which of the following indicates the rate constant of the overall reaction?

21)1( KKK

K

r

f

1)2( K 1)3( KKK rf 1)4( K

K

K

f

r 1)5( K

K

K

r

f

19. When 1.38 g of pure Na was burnt in excess air, a mixture of Na2O and Na2O2 were obtained. This

mixture was treated with excess KI and dil.H2SO4 and the resultant solution was titrated with

0.8 mol dm-3 Na2S2O3, the end point was observed as 50 cm3. What is the mass percentage of Na in

initial sample that has been converted to Na2O2?(Na = 23, O = 16)( 2I- + O22- + 4H+ ⟶ I2 + 2H2O)

(1) 67% (2) 56% (3) 28% (4) 33% (5) 72%

20. Which of the following is incorrect regarding Nitrogen and its compounds?

(1) N is a non-metallic element able to have all the oxidation numbers from – 3 to +5

(2) Its aqueous chloride solution possess bleaching ability as well as disinfectant property.

(3) Thermal decomposition reaction of NH4NO3 is a disproportionation reaction in which neutral

products are formed.

(4) con.HNO3 could oxidize C, S and P to their highest oxidation states.

(5) NH2OH is a white crystalline solid at room temperature (25 ºC) which can act as both acid and

base.

21. In a rigid vessel only n mols of water vapour is present. The absolute temperature of this vessel is

increased to k times. Hence what is mass of water vapour (in grams) that has to be removed in order to

bring the system to initial pressure? (O=16, H=1)

18)1( k

n

18)2( nk 18)1(

)3(

k

kn

18)1(

)4( k

kn 18

)1()5(

k

kn

22. Which of the following statement regarding 3d elements is incorrect?

(1) Ti, V and Cr have high melting points.

(2) Cr shows oxidation states from +2 to +6 in its compounds.

(3) Sc has the highest reducing ability among all the 3d elements.

(4) All of them use 3d electrons along with 4s electrons in compound formation.

(5) Stable aqua complex ions formed by them are of octahedral shape

23. 250 cm3 of 1 mol dm-3, Pb(NO3)2 is taken in an insulated calorimeter at 25 ºC. Same volume of

Na2SO4 with same concentration is added to it. What is the maximum temperature rise that could be

observed in the resultant solution?

(Density of solution = 1000 kg m-3, Specific heat capacity of solution = 4200 J kg-1 K-1, Heat capacity

of calorimeter = 400 J K-1, Standard enthalpy of precipitation of PbSO4(s) = -50 kJ mol-1]

(1) 30 ºC (2) 31 ºC (3) 27 ºC (4) 29 ºC (5) 34 ºC

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24. Which of the following step is incorrect corresponding to electrophilic addition reaction of Propene?

(1)

(2)

(3)

(4)

(5)

25.

Structures of P and Q in the above reaction scheme respectively are,

(1) (2)

(3) (4)

(5)

CH3 – CH = CH2 CH3 – CH – CH3 + H2O +

O

H H H

+

OH2

CH3 – CH – CH3 CH3 – CH – CH3

+

+

H2O:

Br Br

CH3 –– CH –– CH2 CH3 – CH – CH2

+ Br

– :Br

CH3– CH = CH2

Br

CH2 – CH – CH2

+

+ Br:–

Br – Br

Br OH

CH3 –– CH –– CH2 CH3 – CH – CH2Br

+

– HO:

CN

CH= CH2

CO2H

CH2CH2OH

C – NH2

O

CH2CH2OH

C – NH2

O

CH = CH2

C – NH2

O

CH = CH2

O

C – NH2

CH – CH3

OH

C – NH2

O

CH2CH2OH

P Q

P2O5/Δ dil H2SO4

CN

CH= CH2

CN

CH – CH3

OH

CN

CH= CH2

OH

CO2H

CH – CH3

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26. Which of the following statement is incorrect regarding H2S?

(1) H2S can act as both oxidizing agent and reducing agent.

(2) Bond angle decreases in the order of H2Se, H2S and H2O

(3) Conjugate base of H2S is HS ͞

(4) When H2S is passed through acidified Pb(NO3)2(aq), Cu(NO3)2(aq) and Hg(NO3)2(aq) solutions

black precipitates are obtained.

(5) H2 gas is obtained when H2S is passed over hot copper turnings.

27. Electromotive force of the following standard cell is + 0.22 V

Pt(s) / H2(g) / H+

(aq) Cl ͞ (aq) / AgCl(s) / Ag(s)

Which of the following statement is inappropriate?

(1) When the concentration of HCl(aq) is reduced in Ag(s) / AgCl(s) / Cl͞ (aq) electrode, reduction

potential of the electrode increases.

(2) Standard reduction potential of Ag(s) / AgCl(s) / Cl͞ (aq) electrode is + 0.22 V

(3) When the HCl(aq) concentration is reduced in the above cell, its electromotive force decreases.

(4) Ag(s) / AgCl(s) / Cl͞ (aq) electrode acts as a positive terminal.

(5) When HCl(aq) concentration is decreased in Pt(s) / H2(g) / H+(aq) electrode, its reduction

potential becomes negative.

28.

Identify the most possible set of products that can be obtained from the above reaction.

(1)

(2)

(3)

(4)

(5)

29. Which of the following statement is incorrect with respect to polymers?

(1) Proteins are natural condensation polymers.

(2) PVC polymer chains have stronger interactions among them than the polymer chains of Teflon.

(3) All the thermosetting polymers are three dimensional polymers.

(4) Coagulation of rubber latex is efficiently induced by HCOOH rather than CH3COOH

(5) Addition polymers may be found as saturated or unsaturated.

O

C – NH

HO

CH2OH NaOH/Δ

Products

CO2H

HO

CH2OH H2N

CO2–

Na+

HO

CH2O–

Na+ H2N

CO2–

Na+

HO

CH2OH H2N

CO2–

Na+

Na+O

–

CH2OH H2N

CH2O– Na

+ H2N CO2– Na

+

Na+O

–

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30. 2A(g) + 2B(g) → C(g) is an exothermic reaction. It takes place via 3 steps as given in the following

mechanism.

A(g) + B(g) → X(g)

X(g) + B(g) → Y(g)

Y(g) + A(g) → C(g)

Activation energy and the rate equation of above reaction respectively are Ea and R = k[A(g)][B(g)]2.

Hence which of the following energy profile is most appropriate?

For each questions 31 to 40, one or more responses out of the four responses (a), (b), (c), (d) given, is/are

correct response/responses. In accordance with the instructions given on your answer sheet, mark

If only (a) and (b) are correct………………………………………….(1)

If only (b) and (c) are correct………………………………………….(2)

If only (c) and (d) are correct………………………………………….(3)

If only (d) and (a) are correct …………………………………………(4)

If any other combination of responses is correct………….…………..(5)

Abridged version of the above instructions

1 2 3 4 5

Only (a) and (b)

are correct

Only (b) and (c)

are correct

Only (c) and (d)

are correct

Only (d) and (a)

are correct

Any other number of

combination of responses

is correct

Ea

Reaction co-ordinate (1)

Po

ten

tial

en

erg

y

Ea

Reaction co-ordinate (2)

Po

ten

tial

en

erg

y

Ea

Reaction co-ordinate (3)

Po

ten

tial

en

erg

y

Ea

Reaction co-ordinate (4)

Po

ten

tial

en

erg

y

Ea

Reaction co-ordinate (5)

Po

ten

tial

en

erg

y

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31. The following equilibrium was obtained in a closed vessel with a certain amount of R(g) at two

different temperatures T1 and T2

R(g) ⇌ P(g)

The following graphs show the variation of concentration of components at those two different

temperatures T1 and T2

Which of the following statements is/are true regarding the above equilibrium?

(a) Enthalpy of products is greater than that of reactants.

(b) ΔGθ of the reaction becomes, ΔGθ > 0 with the increase of temperature.

(c) With the increase of temperature, the equilibrium constant of the reaction decreases.

(d) This reaction takes place with increase of entropy.

32. Which of the following statements is/are true regarding the given

molecule?

(a) Carbon atoms b, c, d and e are in the same plane.

(b) Electronegativity of the carbon atoms in the benzene ring varies as {Ca = Cf} < {Cb = Ce}

(c) Bond lengths between the carbon atoms varies like {Ca – Cb} = {Cc – Cd} < {Cb – Cc}

(d) Carbon atoms named as a, b, c and d are in the same plane.

33. Which of the following statement/s is/are correct regarding sodium extraction through Down cell

process?

(a) NaCl is heated with MgCl2 to reduce the melting point and electrolyzed.

(b) To separate cathode and anode compartments a selective permeable membrane is used.

(c) Electrolyzed using steel anode and graphite cathode.

(d) Extraction is carried out by passing high electric current in electrolysis process.

34. Which of the following is/are incorrect regarding to a multistep reaction?

(a) If order with respect to a reactant is zero, generally that reactant is included in the steps followed

by rate determining step

(b) If second step of a two-step reaction has high activation energy, the concentration of the

intermediate in reaction mixture increases initially to a considerable amount and then decreases.

(c) If order with respect to a reactant is zero, the concentration of that reactant remains as same during

reaction.

(d) If the concentration of reactant is very much higher than the others then the order with respect to

that reactant must be zero.

d b C = C

CH3

CH3 a

c e

f

Time

At temperature T2

Co

nce

ntr

atio

n

[R(g)]

[P(g)] [R(g)]

[P(g)]

Time

At temperature T1

Co

nce

ntr

atio

n

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35. Correct statements regarding the compounds CH2 = CH – CH2Cl (A) and CH2 = CHCl (B) is/are,

(a) Rate of nucleophilic substitution reaction of A is greater than that of B.

(b) C – Cl bond has partial double bond character in both A and B

(c) Rate of hydrolysis of C6H5CH2Cl is greater than CH2 = CH – CH2Cl but lesser than CH2 = CHCl

(d) Stability of CH2 = CH – CH2+ is greater than that of CH2 = CH+

36. Which of the following statements regarding carbon and its compounds is/are correct?

(a) Solid CO2 is used in food industry and producing artificial rain.

(b) Among the allotropes of carbon, diamond has sp3 hybridized carbon atoms while graphite and

fullerene have sp2 hybridized carbon atoms.

(c) Acidity of oxyacids H2C2O4, H2CO3 and HCOOH varies as H2C2O4 < HCOOH < H2CO3

(d) Metal carbides such as Be2C, Mg2C3 and CaC2 produces CH4, C3H4 and C2H2 gases respectively in

reaction with water.

37. 0.25 mol of N2O4 gas and 0.5 mol of NO2 gas were mixed in a 2 dm3 rigid vessel at 298 K.

N2O4(g)⇌ 2NO2(g)

If the equilibrium constant for this reaction Kc = 1.5 mol dm-3. Which of the following is/are correct

regarding this system?(Qc is the reaction quotient)

(a) Qc < Kc

(b) Qc > Kc

(c) Reaction occurs as to decrease the brown colour density of the system.

(d) Reaction occurs as to increase the total number of moles of gas.

38. A(g) + 2B(g) → C(g)

Which of the following statements regarding the above reaction is/are correct?

(a) If rate of the reaction is R ∝[A(g)][B(g)]2, the reaction should be an elementary reaction.

(b) If only one activated intermediate complex is formed, this reaction should be an elementary

reaction.

(c) If the rate order is higher than that of molecularity, the reaction is a multistep reaction.

(d) If the half life time of the reaction does not depend on the concentration of A(g) then the reaction

should be elementary.

39. Which of the following statements is/are correct regarding 2-butenal?

(a) Product formed in the reaction with Br2(g) shows enantiomerism and diastereomerism.

(b) Product formed in the reaction with CH3MgBr followed by hydrolysis shows enantiomerism.

(c) Product formed in the reaction with LiAlH4 followed by hydrolysis shows diastereomerism.

(d) Product formed in the reaction with HBr shows enantiomerism and diastereomerism.

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40. Which of the following statements is/are most appropriate?

(a) Among the nitrogen compounds N2O gas contributes in greater extent for greenhouse effect.

(b) pH, conductivity and the amount of dissolved oxygen (DO) of an aqueous solution are some

physical parameters usedx to determine the quality of water.

(c) Volcanic eruption is a natural process that contributes to acid rain.

(d) Methane gas released from the alimentary canal (digestive tract) of cattles does not affect the

ozone layer.

In questions No. 41 to 50 two statements are given in respect of each question. From the Table given

below select the response out of the responses (1), (2), (3), (4) and (5) that best fits the two statements

and mark appropriately on your answer sheet.

Response First statement Second statement

(1) True True, and correctly explains the first statement

(2) True True, but does not correctly explain the first statement

(3) True False

(4) False True

(5) False False

First statement Second statement

41. Basic strength of group 1A hydrides increases

down the group.

Polarizing ability of group 1A cations

decreases down the group.

42. Primary alcohols are produced when acid

chlorides are reduced using LiAlH4 followed by

hydrolysis.

Only nucleophilic addition takes place in the

reduction of acid chlorides using LiAlH4

43. Free energy change (ΔG) of a reaction always

becomes more negative when temperature

increases

Generally rate of a reaction increases with

increase of temperature

44. pH values of equal concentrations of

Fe(NO3)2(aq) and Fe(NO3)2(aq) are same.

Hydrolyzing ability of Fe2+ and Fe3+is same

in an aqueous solution.

45. Electrical conductivity of pure water cannot be

changed by adding a piece of Na

The number of H+ ions removed by reduction

is equal to the number of Na+ ions introduced

to the solution, when a piece of Na is added

to pure water.

46. 2P(g) + Q(g) ⇌ 2R(g) This equilibrium reaction

can be shifted towards right by increasing the

pressure by means of reducing the volume.

The rate of forward reaction increases faster

than the rate of backward reaction when

pressure is increased by reducing the volume

in a kinetic chemical equilibrium which takes

place with decrease of number of gas moles.

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47. Soap is obtained by base hydrolysis of vegetable

oils.

Glycerol is obtained as a byproduct in soap

production.

48. Electronegativity of the carbon

atoms named as a, b and c in the

given aniline molecule increases in

the order of c < b < a

Electronegativity of the carbon atom of

benzene attached with an activating group is

very much lesser than the other carbon atoms

of the benzene ring.

49. pH increase of HCl is greater than the pH

increase of CH3COOH when equal

concentrations of aq.HCl and CH3COOH were

diluted by same fold using distilled water.

When aq.HCl is diluted, concentration of

ionized H+ decreases, but when CH3COOH is

diluted, concentration of ionized H+ decreases

with increase of degree of ionization.

50. HCFCs and HFCs can react with hydroxyl

radicals and decay in the troposphere.

Ability of destroying the ozone layer by HFC

is greater than HCFC

NH2 a

b c

[See page two

[KOg;gjpg;GupikAilaJ / All Rights Reserved]

AL/2019/02/E-II(A)

For Examiner’s Use Only

Final Marks

In Numbers

In Letters

Code Numbers

Marking Examiner 1

Marking Examiner 2

Checked by :

Supervised by :

Part Question No. Marks

A

1

2

3

4

B

5

6

7

8

C 9

10

Total

Percentage

Index No. : …..………………………... This question paper consists of 17 pages.

Use of calculators is not allowed.

Universal gas constant R = 8.314 J K−1mol−1

Avagadro’s constant NA = 6.022 × 1023mol−1

Alkyl groups can be written in short form as follows.

Eg : CH3CH2- can be written as

Part A – Structured Essay ( Pages 2 - 10 )

Answer all the questions on the question paper itself.

Write your answers in the space provided for each question.

Please note that the space provided is sufficient for the answer and that extensive answers are not

expected.

Part B – Essay ( Pages 11 - 17 )

Answer four questions altogether choosing two questions from each section. Use the answer sheets

provided for this purpose.

Annex part B and C to A placing part a on top and hand it over to the examination Supervisor at the

end of the given time.

You are permitted to remove only Parts B and C of the question paper from the Examination Hall.

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AL/2019/02/E-II(A)

Do not

write

anything

here.

01. a) Consider the first ten elements of the periodic table. Write the relevant chemical symbol of

the element that is suitable for the following descriptions.

(i)

I. Having an electron that experiences effective nuclear charge as same as its

nuclear charge : …………………..…………

II. Having the lowest oxidation state : ………………….…………

III. Having the highest electronegativity : ………………….…………

(ii) Write the chemical formula of the compounds formed by the element identified in

question (II) above with the elements identified in question (I) and (III) separately.

……………………………………………………………………………………………

(iii) Identify the compound that has the central atom with higher electronegativity among the

compounds you have written in question (ii). State the reasons for its higher

electronegativity.

………………………………………………………………………………………………

………………………………………………………………………………………………

………………………………………………………………………………………………

b) Chlorine dioxide (ClO2) disproportionates in alkali medium and forms two oxyanions of

chlorine with oxidation numbers +1 and +5 at room temperature

(i) Write the chemical formula and IUPAC name of the anion formed by the oxyanion with

+5 oxidation state in aqueous state.

…………………………………………………………………….………………………

(ii) Draw all the possible resonance structures for the anion in (i) above

Part A – Structured Essay Answer all four questions on this paper itself.

(Each question carries 10 marks)

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(iii) Draw the relevant resonance hybrid for the above anion and describe the relative

contribution of the above resonance structures drawn in (ii) above for the resonance

hybrid

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

(iv) Compare the bond lengths and bond angles of the anion drawn in part (i) above with

appropriate reasons.(quantitative values are not necessary)

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

(v) Draw the stable Lewis structure of HClO2

(vi) Consider the Chlorine atom and the oxygen atom joined with hydrogen in the Lewis

structure you have drawn above for HClO2 and complete the following table.

Fact Cl O

Hybridization

Electron pair geometry

Geometrical shape

Oxidation number

c) Arrange the following species in the increasing order of the character given in the

parenthesis

(i) F, Cl and Br (Electron affinity)

…………………………………………………………………………………………………

(ii) CH4, NH3 and NF3 (Dipole moment)

…………………………………………………………………………………………………

(iii) CF4, CBr4 and CCl4 (Electronegativity of C)

………………………………………………………………………...….……………………

(iv) Na+(g), Mg2+(g) and Al3+(g) (Hydration enthalpy)

………………………………………………………………………...………………………

(v) CH3OH, NaCl and I2 (Strength of interaction formed with water molecules)

……………………………………………………………………..……….…………………

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02. a) When white solid A was strongly heated, basic oxide B and colorless gas C were obtained.

Gas C did not change the colour of acidified K2Cr2O7 solution. When A was reacted with

dil.HCl, solution D was obtained. Solution D gave white precipitate E with (NH4)2C2O4

solution. Precipitate E is insoluble in dil.Acetic acid solution. The substance obtained in the

reaction of A with con.HCl gave Orange-red (brick red) flame in flame test.

i. Identify the species from A to E.

A……………………………………………………………………………………

B……………………………………………………………………………………

C……………………………………………………………………………………

D……………………………………………………………………………………

E……………………………………………………………………………………

ii. Write the balanced ionic equation for the thermal decomposition reaction of solid

state E at 1000 ºC

………………………………………………………………………………..………

………………………………………………………………………………………..

iii. A bleaching agent was obtained in treatment of B with water followed by passing

of diatomic gas X2 under cold conditions.

1. What is the chemical symbol of X?

X……………………………………………...…………………………………

2. Identify the bleaching agent.

………………………………………..…………….……………………………

3. Write the balanced chemical equation for obtaining the bleaching agent.

…………………………………..……………….………………………………

iv. Give the variation trend of the thermal stability, by considering the similar

compounds formed by all the elements in the same group of element present as

cation in compound A.

………………………………………………………………………………………

State the reasons for this variation.

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

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v. Plot the boiling point variation trend of hydrides of elements in the same group of

X

vi. When gas C was heated with coke, it was reduced to produce a diatomic gas.

1. Identify the diatomic gas

…………………………………………………………………………………

2. Mention two uses of the above diatomic gas.

…………………………………………………………….……………………

……………………………………………………………………….…………

b)

i. Identify A, B, C and D

A………………………………………………C……………………………………

B……………………………………………....D………………..……..……………

ii. Write balanced chemical equations for obtaining B, C and D from A

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

iii. Solution L has been obtained when gas B reacted with diatomic gas (M2) and

water. The concentrated L is a viscous liquid.

1. Identify M2 and L

M2…………………………………………L….………………………………

2. Write balanced chemical equation corresponding to the production of L

………………………………………………..…………………………………

Colourless solid (A)

dil.HCl(aq)

NaOH(aq)

Heating

Brown coloured gas (B)

Colourless basic gas (C)

Inert diatomic gas (D)

No any solid residue has been obtained in continuous heating of A

Hydride

Bo

ilin

g p

oin

t

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3. Write the balanced chemical equation for the photochemical reaction of L.

…………………………………………….……………………………………

4. Write balanced chemical equations for the oxidation of Carbon and Sulfur by L

with appropriate conditions.

………………………………………………….……….……………………………………………………………………….…….……………………………

5. Write one balanced chemical reaction in which L acts as a base

……………………………………………….…………………………………

6. L can be produced from less stable compound Q, without using any other

reagents

i. Identify Q.

…………………………………………………….………….…………………

ii. Write the balanced chemical reaction for the formation of L from Q.

……………………………………………….……………………….…………

iii. Write the type of reaction in which L forms from Q.

……………………………………………………………………..……………

iv. Draw the Lewis structures of Q and L.

03. a)

The above reaction takes place via following three steps

Step I – + H+ (Slow step)

Step II – + H+ (Fast step)

Step III – + I2 + HI (Fast step)

(i) If K is the rate constant and R is the rate of reaction, Write the rate equation for

this reaction.

……………………………….……………………………………………………

CH3 – C = CH2

OH

CH3 – C – CH3

O

CH3 – C – CH3

+OH

CH3 – C = CH2

OH

CH3 – C – CH2I

O

CH3 – C – CH3

+OH

CH3 – C – CH3

O

+ I2

H+

CH3 – C – CH2I

O

+ HI

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(ii) What is the overall order of this reaction?

……………………………………………………………………………………

(iii) What is the order with respect to I2? State the reason for your answer.

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

(iv) State the role of H+ in the above reaction. Give reason.

……………………………………………………………………………………

……………………………………………………………………………………

(v) What is the conclusion that can be made from (iv) above?

……………………………………………………………………………………

(vi) Draw relevant graph for the variation of concentration of CH3COCH3 vs time

and also draw a graph for the variation of log(rate) vs log [CH3COCH3] while

concentrations of all other reactants are kept as constant.

b) At 127 °C, 0.02 mols of gas P was kept in a rigid vessel of volume 2 dm3. Gas P was

dissociated as given below in the presence of solid catalyst.

2P(g) Q(g) + 2R(g)

The following graph shows the variation of concentration of P(g)

5 10 20 15

[P] / mol dm-3

Time / s

0.020

0.015

0.010

0.005

[CH

3C

OC

H3]

Time

log(R

ate)

log [CH3COCH3]

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(i) Write the rate equation by considering p and k as rate order and rate constant

respectively.

……………………………………………………………………………………

(ii) Deduce the value of p by giving reasons.

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

(iii) What is the half life time of the reaction?

……………………………………………………………………………………

(iv) If the half life time of the reaction is given by t1 2⁄ = 0.693k then find the value of

rate constant k.

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

(v) Find the pressure inside the vessel, if 25% of the initial amount of P has

dissociated. Assume that volume of the catalyst could be neglected.

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

……………………………………………………………………………………

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04. a) A, B, C and D are structural isomers with molecular formula C4H11N. They form E, F, G

and H respectively when treated with NaNO2/HCl. All these four products reacted with

PCl5 and give white fume. Only A exhibited optical isomerism among A, B, C and D.

Compound B has same skeletal carbon arrangement as in A. Immediate turbidity is

observed when H is treated with ZnCl2/con.HCl

i. Draw the structures of A, B, C and D in the boxes given below. (Stereoisomeric

forms are not necessary)

ii. Draw the structure of compound among E, F, G and H that can exhibit

stereoisomerism.

iii. Product obtained by the dehydration of compound in (ii) above using con.H2SO4

also shows stereoisomerism. Draw stereoisomeric forms of products obtained in

dehydration

b) Consider the following reaction scheme

CH3C ≡ C – H CH3MgBr

Dry ether

P

+

Q

1)

2) H2O

C – C ≡ C – CH3

OH

CH3

R

C – CH2CH2CH3

Br

CH3

COCH3

A

C

B

D

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Compound P formed in this reaction is a strong base. R gives hydrogen gas in

reaction with sodium. Draw the structures of P, Q and R in the boxes given below.

c) Write the major products that can be obtained in the reactions given below.

1.

2.

3.

4.

5.

6.

7.

8.

R P Q

C6H5N2+Cl- C6H5OH / NaOH

0-5 ºC

CH3CH = CH – C – OH 1) LiAlH4

2) H2O

O

CH3CHO 1) 2,4 DNP

2) Dehydration

CH3CH = CH2 R2O2

HBr

CH3CH = CH2 Con H2SO4

CHO

CH3COCl

Dry AlCl3

CH2 – CH – CH3 Con. H2SO4

Δ OH

CH2 = CH – CH2Cl

Dry AlCl3

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Universal gas constant R = 8.314 J K−1 mol−1

Avagadro’s constant NA = 6.022 × 1023 mol−1

Answer only two questions from each Part – B and Part – C (Each question carries 15 marks)

Part B - Essay

05. The following equilibrium was established when SO2(g) and O2(g) gases were taken in the mole ratio

of 2 : 1 at 28 °C, in a closed vessel with the presence of catalyst.

2SO2(g) + O2(g) ⇌ 2SO3(g)

The partial pressure of SO2(g) at equilibrium state was 24 kPa and the total pressure was found

to be 104 kPa.

i. Calculate the mole fraction and partial pressure of O2 gas at equilibrium

ii. Calculate the partial pressure of SO3(g), hence find the equilibrium constant KP

iii. Calculate the equilibrium constant KC at 28 °C (At 28 °C, RT = 2500 J mol-1)

iv. If a reaction was initiated at 28 °C in a closed vessel, the partial pressures of SO3(g), SO2(g)

and O2(g) were 80 kPa, 70 kPa and 20 kPa respectively. Calculate the reaction quotient QP

at initial moment. State the direction of reaction shift with appropriate reasons by

considering the QP value .

v. What is the equilibrium constant with respect to Standard pressure?

(b) Formation enthalpies of some compounds are given below.

Compound ΔHθf (kJmol-1)

C7H16(l) -200

CO2(g) -400

H2O(l) -300

i. Find the standard combustion enthalpy of C7H16 liquid using the above data.

ii. Find the mass of liquid water at 100 °C that could be converted into water vapour at 100°C

by the combustion of 200g of C7H16 liquid. (10% of total heat energy supplied is lost to

environment. Latent heat of vapourization of water is 45 kJ mol-1)

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iii. At 250C, rate of respiration of a healthy human is 15 times per minute. In each inspiration

the volume of inhaled air is 500 cm3. The volume percentage of O2 in the inhaled air is 21%

and in the same volume of exhaled air is 16%. Assume that all the oxygen is utilized for the

combustion of C6H12O6.

Atmospheric pressure = 1 x 105 Pa, ΔHθC[C6H12O6(s)] = - 2800 kJ mol-1. Hence,

a. What is the amount of C6H12O6 involved to combustion in one day?

b. Calculate the amount of heat energy released in 1 day?

06. (a) i. Show that pH of C mol dm-3 solution of CH3COOH(aq) can be given by,

pH = ½ pKa – ½ log C;

Here Ka – dissociation constant of weak acid

ii. If the dissociation constant of CH3COOH Ka = 2x10-5 mol dm-3, find the pH of the solution

where the concentration of CH3COOH is 0.1 mol dm-3

ii. A 25.0 cm3 of 0.1 mol dm-3 CH3COOH(aq) solution is taken in a titration flask and titrated

using 0.1mol dm-3 NaOH(aq) solution in the presence of relevant indicator. Find the pH of

solution inside the flask separately when each of the following volumes of NaOH was added

into the titration mixture.

Volume of NaOH(aq) added – 10.00 cm3, 24.95 cm3, 25.05 cm3, 30.00 cm3

iii. Show that the pH of resultant solution at equivalente point can be given as,

pH = ½ pKa + ½ pKw + ½ log S (Here, S – concentration of Salt or the concentration of

Conjugate base)

Therefore, find the pH at equivalence point.

iv. Show the variation of pH of the solution against the volume of NaOH(aq) added in a suitable

graph.

v. Choose one suitable indicator for the above titration from the following table. Provide

reasons for your choice.

Indicator pKIn

Methyl orange

Bromothymol blue

Phenolphthalein

Methyl red

3.7

7.1

9.4

5.0

(b) An acidified aqueous solution contains 0.1 mol dm-3 concentration of M2+(aq) and 0.1 mol dm-3

concentration of N2+(aq) . H2S(g) is passed through this solution to produce the concentration of

H2S(aq) as 0.1 mol dm-3 .

Ksp(MS) = 1.6 x10-24 mol2 dm-3, Ksp(NS) = 6.3 x10-18mol2 dm-6

Ka1(H2S) = 9.1x10-8 mol dm-3, Ka2(H2S) = 1.0 x10-19 mol dm-3

i. Calculate the minimum concentration of S2-(aq) that is required for the precipitation of MS.

ii. What should be the lowest pH at which the solution must be kept in order to precipitate MS?

iii. Calculate the minimum concentration of S2-(aq) that is required for the precipitation of NS.

iv. What can be the pH range of solution to separate both cations?

v. Deduce minimum [H3O+(aq)] concentration in the solution for the precipitation of M2+(aq)

and to prevent the precipitation of N2+(aq).

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07. (a) Carry out the following conversion in not more than 9 steps by using only the chemicals given in

the list

CH3CH2CH2COCH3 →

Mg, con.HBr, HBr(g),dry ether, HCHO, C6H5NH2,

NaBH4, C2H5OH, KOH, H2O, PCC

(b) Identify R1 – R5, X1 – X4 and Y1 – Y3 to complete the following reaction scheme

(c) i. Write the structure of product formed in the reaction between CH3CH = CH2 and

con.H2SO4. Give the corresponding mechanism for the above reaction.

ii. Among propene and 2-methyl propene which compound reacts with HBr(g) at high rate,

State appropriate reasons for your answer.

iii. Arrange HCHO, CH3CHO and CH3COCH3 in the increasing order of rate of nucleophilic

addition reaction. Briefly explain the reasons for your answer.

CH3CH2

CH3CH2

CH – CH = N

C – O – CH2

O

C ≡ C – CH3

NaOH /∆

X1

X2

X3

X4

R1

R2

R3

C – O – CH2 CH – CH – CH3

O

Br Br

NO2

Y1

Y2

Y3

R4

R5

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Part – C

08. (a) Solution A has two cations and two anions. Following experiments have been carried out and

relevant observations were noted to identify the ions present in the solution.

For cations

Experiment Observations

(1) Solution A is acidified with HCl and H2S

gas has been bubbled through the solution

Black precipitate (P) is formed

(2) Filtrate from (1) above is boiled and then

heated with HNO3 solution. NH4Cl(aq) /

NH4OH(aq) has been added to resultant

solution

A clear solution has been obtained

(3) (NH4)2CO3(aq) is added to solution from

(2) above.

A clear solution has been obtained

(4) Excess NaOH(aq) is added to filtrate from

experiment (3 ) above.

White precipitate (R) has been obtained

(5) Charcoal block test is carried out with

white precipitate (R) Pink colour residue is obtained

(6) After boiling P with dil.HNO3(aq), excess

amount of ammonia solution has been

added

Dark blue coloured complex compound

(E) has been obtained

For anions

(7) dil.HCl solution is added to A No observation is obtained

(8) solution A is boiled with Al powder and

NaOH(aq)

Colourless gas X with pungent smell is

released

(9) Another part of A is treated with FeSO4

solution and kept in the air for some time

The colour of solution has turned blood

red and the colour intensity increased with

time

i. Identify the two cations and two anions in the solution (reasons are not required)

ii. Write the chemical formula of chemical species P, E, R and X.

iii. Write the balanced ionic equation for the reactions in (8) above

iv. Explain the reason for the addition of NH4Cl(aq) before the addition of NH4OH(aq) in test of

cation (2)

(b) A 4.0g of sample containing CuS, FeS, ZnS and an inert impurity was treated with excess

amount of 0.3 mol dm-3, 200 cm3 of acidified KMnO4 solution. Then solution was heated well

to remove the produced SO2 gas in the solution and an appropriate method was also applied to

remove the Mn2+ formed in the reduction of KMnO4 .The final solution obtained was named as

Z.

Procedure: 01

100 cm3 of solution Z was taken and titrated with 1 mol dm-3 Fe2+ solution. The required

volume was 25 cm3

Procedure: 02

50 cm3 of solution Z was taken and mixed with excess NH3, the precipitate obtained was filtered

and heated until a constant mass was obtained. The mass of remaining residue was 0.16 g

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Procedure: 03

Filtrate from procedure 02 have been treated with dilute acid to neutralize the ammonia. After

that excess of KI(aq) was added . 0.2 mol dm-3, 30.0 cm3 of Na2S2O3 solution was required to

titrate the resultant solution.

1. Write balanced chemical equations for the above reactions.

2. Calculate the mass percentages of CuS, FeS and ZnS in the given sample

09. (a) Consider the following flow chart regarding industrial processes. Here X1→ X5 denotes natural

resources and P1 → P16 denotes products. Identify natural resources X1→ X5 and products P1 → P16.

P1 and X2 – Catalyst in ammonia production

P5 – used domestically for personal

hygiene

P11 – Bleaching agent

P14 – used in the production of bakery

products

(b) Some substances released from the vehicles’ exhaust react in the presence of sunlight and

cause bad impacts on human beings.

i. How do we call the above process that causing this bad impacts?

ii. What are the harm full substances resulted from the above process?

iii. This process takes place in the lower atmosphere after the formation of O3. give the

reactions related with formation of ozone.

iv. Mention the problems faced by human from the above process.

v. State three pre-cautionary measures to prevent from the above mentioned bad effect.

vi. Water can be purified using O3. Give one advantage and a drawback from using this

method of purification.

P16

+

+

+

+

X3 X4

P5

P4

P7 P10

P11

Concentrating

Electrolysis

P8

P9 P12

NH3

P13 P14

P15

H2O

Δ

Δ

P6

P3

X1

P12 P2 + +

P1

Cr, Ni

+

X5

X2

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(c) Some organic compounds related with polymer industry are given below.

i. Which of the above molecule forms a polymer with a double bond in its repeating units?

Give the relevant repeating unit also.

ii. Which of the above molecules could form thermosetting condensation polymers? Give

the repeating units and name of the polymer.

iii. Which of the above substance could offer thermoplastic polymer having higher resistance

for heat? Give the structure of this polymer. State the reason for its higher resistance to

heat.

iv. Give the substances forming the three dimensional cross condensation polymer. Mention

the relevant catalyst that can be used in the above polymerization.

v. What is the substance used in the regifoam production? State its repeating unit.

10. (a) A, B, C and D are four complex compounds of Chromium. Their formulae are given below

as, CrO6H12Cl3, CrO5H10Cl3, CrO4H8Cl3 and CrO3H6Cl3 respectively. The geometrical shape

of the complex ion part is octahedral and maximum of two types of ligands can be present

around the central atom of each complex, while the non-coordinated part belongs to the same

kind. In all these compounds Chromium has same oxidation number.

i. What is the oxidation number of Cr in the above complex compounds?

ii. Write the electronic configuration of Cr in the above compounds.

iii. Give the structural formula of A, B, C and D

iv. Write the IUPAC names of A, B, C and D

v. Solution S was prepared using each 1 mol of A, B, C and D. excess amount of

AgNO3(aq) was added to solution S and the precipitate obtained was filtered, dried and

weighed. What is the mass of precipitate obtained? (Ag =108, Cl =35.5)

CH = CH2

(A)

OH

(E)

C2F4

(F)

CH2 = C – CH = CH2

CH3

(D)

HO – CH2CH2 – OH

(G)

HCHO

(B)

COOH

(C)

COOH

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(b) 1. Following diagram depicts an electro chemical cell

The cell reaction is given as follows when the cell operates.

6Cl-(aq) + 2Au3+(aq) → 3Cl2(g) + 2Au(s)

Voltmeter reading when the switch S is opened is 0.14 V

i. Write down the oxidation half-cell reaction.

ii. Write down the reduction half-cell reaction

iii. Give the cell notation.

iv. If the standard electrode potential of Pt(s) /Cl2(g) /Cl-(aq) electrode is +1.36 V then find

the standard electrode potential of Au3+(aq) /Au(s)

v. When switch S is closed the bulb begins to glow. State what would happen to the

voltmeter reading at this state, Explain?

2. In an electrolysis, 100 cm3 0.1 mol dm-3 LiBr solution was electrolyzed by using Mg

electrodes. A precipitate formation was observed when 100 mA of current was allowed to

pass through the solution for a certain time.

I. Write the reaction which takes place in anode

II. Write the reaction which takes place in cathode

III. What is the net reaction takes place during the electrolysis?

IV. State the approximate time period at which precipitate begins to form from starting

time of electrolysis. ( Ksp(Mg(OH)2) = 12 × 10-12 mol3 dm-9, 1 F = 96500 C)

S

V

Au

Au3+(aq, 1moldm-3)

Cl2(g)

Pt(s)

Cl-(aq, 1moldm-3) Salt bridge