CBSE Class 12 Chemistry Question Paper 2020 Set 56-3-2

H$moS> Z§.
Code No. 56/3/2
amob Z§. narjmWu H$moS >H$mo CÎma-nwpñVH$m Ho$ _wI-n¥ð
Roll No. >na Adí` {bIo§ &
Candidates must write the Code on the
title page of the answer-book.

ZmoQ> NOTE
(I) H¥$n`m Om±M H$a b| {H$ Bg àíZ-nÌ _o§ _w{ÐV (I) Please check that this question
n¥ð> 19 h¢ & paper contains 19 printed pages.

(II) àíZ-nÌ _| Xm{hZo hmW H$s Amoa {XE JE H$moS (II) Code number given on the right
>Zå~a H$mo N>mÌ CÎma-nwpñVH$m Ho$ _wI-n¥ð> na hand side of the question paper
{bI| & should be written on the title page of
the answer-book by the candidate.
(III) H¥$n`m Om±M H$a b| {H$ Bg àíZ-nÌ _| (III) Please check that this question
>37 àíZ h¢ & paper contains 37 questions.
(IV) H¥$n`m àíZ H$m CÎma {bIZm ewê$ H$aZo go (IV) Please write down the Serial
nhbo, CÎma-nwpñVH$m _| àíZ H$m H«$_m§H$ Number of the question in the
Adí` {bI| & answer-book before attempting it.
(V) Bg àíZ-nÌ H$mo n‹T>Zo Ho$ {bE 15 {_ZQ >H$m (V) 15 minute time has been allotted to
g_` {X`m J`m h¡ & àíZ-nÌ H$m {dVaU read this question paper. The
nydm©• _| 10.15 ~Oo {H$`m OmEJm & question paper will be distributed
10.15 ~Oo go 10.30 ~Oo VH$ N>mÌ Ho$db at 10.15 a.m. From 10.15 a.m. to
10.30 a.m., the students will
àíZ-nÌ H$mo n‹T>|Jo Am¡a Bg Ad{Y Ho$ Xm¡amZ read the question paper only and
do CÎma-nwpñVH$m na H$moB© CÎma Zht {bI|Jo & will not write any answer on the
answer-book during this period.

agm`Z {dkmZ (g¡ÕmpÝVH$)
CHEMISTRY (Theory)

{ZYm©[aV g_` : 3 KÊQ>o A{YH$V_ A§H$ : 70
Time allowed : 3 hours Maximum Marks : 70

.56/3/2 1 P.T.O.

gm_mÝ` {ZX}e :
{ZåZ{b{IV {ZX}em| H$mo ~hþV gmdYmZr go n{‹T>E Am¡a CZH$m g™Vr go nmbZ H$s{OE :
(i) `h àíZ-nÌ Mma IÊS>m| _| {d^m{OV {H$`m J`m h¡ – H$, I, J Ed§ K & Bg àíZ-nÌ _|
37 àíZ h¢ & g^r àíZ A{Zdm`© h¢ &
(ii) IÊS> H$ _| àíZ g§»`m 1 go 20 VH$ A{V bKw-CÎmar` àH$ma Ho$ àíZ h¢, àË`oH$ àíZ 1 A§H$ H$m
h¡ & àË`oH$ àíZ H$m CÎma EH$ eãX `m EH$ dmŠ` _| Xr{OE &
(iii) IÊS> I _| àíZ g§»`m 21 go 27 VH$ bKw-CÎmar` àH$ma Ho$ àíZ h¢, àË`oH$ àíZ 2 A§H$m| H$m
h¡ &
(iv) IÊS> J _| àíZ g§»`m 28 go 34 VH$ XrK©-CÎmar` àH$ma-I Ho$ àíZ h¢, àË`oH$ àíZ 3 A§H$m| H$m
h¡ &
(v) IÊS> K _| àíZ g§»`m 35 go 37 VH$ XrK©-CÎmar` àH$ma-II Ho$ àíZ h¢, àË`oH$ àíZ 5 A§H$m| H$m
h¡ &
(vi) àíZ-nÌ _| H$moB© g_J« {dH$ën Zht h¡ & VWm{n, Xmo-Xmo A§H$m| Ho$ Xmo àíZm| _|, VrZ-VrZ A§H$m| Hoo$
Xmo àíZm| _| VWm nm±M-nm±M A§H$m| Ho$ VrZm| àíZm| _| AmÝV[aH$ {dH$ën {X`m J`m h¡ & Eogo àíZm| _|
go Ho$db EH$ hr {dH$ën H$m CÎma Xr{OE &
(vii) BgHo$ A{V[aº$, Amdí`H$VmZwgma, àË`oH$ IÊS> Am¡a àíZ Ho$ gmW `Wmo{MV {ZX}e {XE JE h¢ &
(viii) Ho$ëHw$boQ>a AWdm bm°J Q>o~b Ho$ à`moJ H$s AZw_{V Zht h¡ &

IÊS> H$
{XE JE AZwÀN>oX H$mo n{‹T>E VWm àíZ g§»`m 1 go 5 Ho$ CÎma Xr{OE : 15=5

AmdV© gmaUr Ho$ d-ãbm°H$ ‘| dJ© 3 go 12 Ho$ VÎd AmVo h¢ Omo g§H«$‘U VÎdm| Ho$ ê$n ‘| OmZo
OmVo h¢ & gm‘mݶ ê$n go BZ VÎdm| H$m Bbo³Q´>m°{ZH$ {dݶmg (n – 1) d1–10 ns1–2 h¡ & BZ
na‘mUwAm| Ho$ Cnm§{V‘ D$Om© ñVa Ho$ d-H$jH$m| ‘| Bbo³Q´>m°Z ^ao OmVo h¢ VWm Bg àH$ma
g§H«$‘U YmVwAm| H$s VrZ n§{³V¶m± AWm©V² 3d, 4d d 5d loUr àmßV hmoVr h¢ & VWm{n Zn, Cd
Am¡a Hg H$mo g§H«$‘U VÎd Zht ‘mZm OmVm h¡ & g§H«$‘U VÎd Hw$N> A{^bmj{UH$ JwU Xem©Vo
h¢ O¡go n[adV©Zr` Am°³grH$aU AdñWmE±, g§Hw$b {Z‘m©U, a§JrZ Am¶Zm| Am¡a {‘lmVwAm| H$m
~ZZm, CËàoaH$s¶ g{H«$¶Vm Am{X & g§H«$‘U YmVwE± (Zn, Cd Am¡a Hg Ho$ AndmXm| Ho$ gmW)
H$R>moa hmoVr h¢ Am¡a BZHo$ JbZm§H$ CÀM hmoVo h¢ &
.56/3/2 2

General Instructions :
Read the following instructions very carefully and strictly follow them :
(i) This question paper comprises four Sections – A, B, C and D. There are
37 questions in the question paper. All questions are compulsory.
(ii) Section A – Questions no. 1 to 20 are very short answer type questions,
carrying 1 mark each. Answer these questions in one word or one sentence.
(iii) Section B – Questions no. 21 to 27 are short answer type questions, carrying
2 marks each.
(iv) Section C – Questions no. 28 to 34 are long answer type-I questions, carrying
3 marks each.
(v) Section D – Questions no. 35 to 37 are long answer type-II questions, carrying
5 marks each.
(vi) There is no overall choice in the question paper. However, an internal choice
has been provided in 2 questions of two marks, 2 questions of three marks and
all the 3 questions of five marks. You have to attempt only one of the choices in
such questions.
(vii) In addition to this, separate instructions are given with each section and
question, wherever necessary.
(viii) Use of calculators and log tables is not permitted.

SECTION A

Read the given passage and answer the questions number 1 to 5 that follow : 15=5

The d-block of the periodic table contains the elements of the groups
3 – 12 and are known as transition elements. In general, the electronic
configuration of these elements is (n – 1) d1–10 ns1–2. The d-orbitals of the
penultimate energy level in their atoms receive electrons giving rise to
the three rows of the transition metals i.e., 3d, 4d and 5d series.
However, Zn, Cd and Hg are not regarded as transition elements.
Transition elements exhibit certain characteristic properties like variable
oxidation states, complex formation, formation of coloured ions and
alloys, catalytic activity, etc. Transition metals are hard (except Zn, Cd
and Hg) and have a high melting point.
.56/3/2 3 P.T.O.

1. Zn, Cd Am¡a Hg g§H«$‘U VÎd ³¶m| Zht ‘mZo OmVo h¢ ?

2. 3d loUr H$m H$m¡Z-gm g§H«$_U YmVw n[adV©Zr¶ Am°³grH$aU AdñWmE± Zht Xem©Vm h¡ ?

3. g§H«$‘U YmVwE± Am¡a CZHo$ ¶m¡{JH$ CËàoaH$s¶ g{H«$¶Vm ³¶m| Xem©Vo h¢ ?

4. g§H«$‘U YmVwAm| Ho$ JbZm§H$ CÀM ³¶m| hmoVo h¢ ?

5. Obr¶ {db¶Z ‘| Cu2+ Am¶Z a§JrZ ³¶m| hmoVm h¡ O~{H$ Zn2+ Am¶Z a§JhrZ hmoVm h¡ &

àíZ g§»`m 6 go 10 EH$ eãX CÎmar¶ h¢ : 15=5

6. o-S>mB³bmoamo~oݵOrZ Am¡a p-S>mB³bmoamo~oݵOrZ ‘| go {H$gH$m JbZm§H$ CÀMVa h¡ ?

7. O~ ~oݵOrZ S>mBEoµOmo{Z¶‘ ŠbmoamBS>, EWoZm°b Ho$ gmW A{^{H«$¶m H$aVm h¡ Vmo àmßV CËnmX
{b{IE &
8. NaCl Ho$ Obr¶ {db¶Z H$m {dÚwV²-AnKQ>Z H$aZo na H¡$WmoS> na àmßV CËnmX {b{IE &

9. Cg S>mBg¡Ho$amBS> H$m Zm‘ {b{IE Omo Ob-AnK{Q>V hmoH$a ½byH$mog Am¡a J¡b¡³Q>mog XoVm h¡ &
10. ZtX bmZo dmbr Jmo{b¶m| ‘| {H$g àH$ma Ho$ amgm¶{ZH$ nXmW© à¶w³V hmoVo h¢ ?

àíZ g§»`m 11 go 15 ~hþ{dH$ënr¶ àíZ h¢ : 15=5

11. {ZåZ{b{IV KCl Ho$ {db¶Zm| ‘| go {H$gH$m {d{eîQ> MmbH$Ëd ‘mZ CÀMV‘ hmoJm ?
(A) 0·5 M
(B) 0·01 M
(C) 0·1 M
(D) 1·0 M

12. A{^{H«$¶m H$s {H$g H$mo{Q> Ho$ {bE A{^{H«$¶m doJ Ed§ doJ pñWam§H$ H$s BH$mB© g‘mZ hmoVr
h¡ ?
(A) àW‘
(B) eyݶ
(C) {ÛVr¶
(D) AY©

.56/3/2 4

1. Why are Zn, Cd and Hg non-transition elements ?

2. Which transition metal of 3d series does not show variable oxidation
states ?

3. Why do transition metals and their compounds show catalytic activity ?

4. Why are melting points of transition metals high ?

5. Why is Cu2+ ion coloured while Zn2+ ion is colourless in aqueous
solution ?

Questions number 6 to 10 are one word answers : 15=5

6. Out of o-dichlorobenzene and p-dichlorobenzene, which has higher
melting point ?

7. Write the product when benzene diazonium chloride reacts with ethanol.

8. Write the product obtained at cathode on electrolysis of aqueous solution
of NaCl.

9. Name the disaccharide which on hydrolysis gives glucose and galactose.

10. What type of chemical substances are used in sleeping pills ?

Questions number 11 to 15 are multiple choice questions : 15=5

11. Which of the following solutions of KCl will have the highest value of
specific conductance ?
(A) 0·5 M
(B) 0·01 M
(C) 0·1 M
(D) 1·0 M

12. The unit of the rate of reaction is the same as that of the rate constant
for a
(A) first order reaction
(B) zero order reaction
(C) second order reaction
(D) half-order reaction
.56/3/2 5 P.T.O.

13. {ZåZ{b{IV A{^{H«$¶mAm| ‘| go {H$gHo$ Ûmam ’$’$moboXma Vm±~m àmßV hmoVm h¡ ?
(A) Cu2+ + Zn  Zn2+ + Cu
(B) Cu2S + FeS  2 Cu + FeS2
(C) Cu2S + 2 Cu2O  6 Cu + SO2
(D) Cu2O + C  2 Cu + CO

14. EDTA h¡
(A) EH$X§Vwa {bJÝS>
(B) {ÛX§Vwa {bJÝS>
(C) C^X§Vr {bJÝS>
(D) fQ>X§Vwa {bJÝS>
15. àmoQ>rZm| H$s {ÛVr¶H$ g§aMZm ‘| Eo‘rZmo Aåbm| Ho$ AUwAm| Ho$ H$m¡Z -go ^mJ Amng ‘| hmBS´>moOZ
Am~§Y go Ow‹S>o hmoVo h¢ ?
(A) NH2 g‘yh
(B) COOH g‘yh
(C) Am¡a – NH  g‘yh

(D) Cn`w©³V ‘| go H$moB© Zht
àíZ g§»`m 16 go 20 Ho$ {bE, Xmo H$WZ {XE JE h¢ {OZ_| EH$ H$mo A{^H$WZ (A) VWm Xÿgao
H$mo H$maU (R) Ûmam A§{H$V {H$`m J`m h¡ & BZ àíZm| Ho$ ghr CÎma ZrMo {XE JE H$mo S>m| (i),
(ii), (iii) Am¡a (iv) _| go MwZH$a Xr{OE : 15=5
(i) A{^H$WZ (A) Am¡a H$maU (R) XmoZm| ghr H$WZ h¢ Am¡a H$maU (R), A{^H$WZ (A)
H$s ghr ì¶m»¶m h¡ &
(ii) A{^H$WZ (A) Am¡a H$maU (R) XmoZm| ghr H$WZ h¢, naÝVw H$maU (R),
A{^H$WZ (A) H$s ghr ì¶m»¶m Zht h¡ &
(iii) A{^H$WZ (A) ghr h¡, naÝVw H$maU (R) µJbV H$WZ h¡ &
(iv) A{^H$WZ (A) µJbV h¡, naÝVw H$maU (R) ghr H$WZ h¡ &
16. A{^H$WZ (A) : µ’$m°{‘©H$ Aåb H$s Anojm Eogr{Q>H$ Aåb A{YH$ à~b hmoVm h¡ &
H$maU (R) : Eogr{Q>H$ Aåb ‘| Bbo³Q´>m°Z XmVm ‘o{Wb g‘yh O – H Am~§Y H$m {dXbZ
H${R>Z H$a XoVm h¡ &
.56/3/2 6

13. By which of the following reactions is blister copper obtained ?
(A) Cu2+ + Zn  Zn2+ + Cu
(B) Cu2S + FeS  2 Cu + FeS2
(C) Cu2S + 2 Cu2O  6 Cu + SO2
(D) Cu2O + C  2 Cu + CO

14. EDTA is a
(A) monodentate ligand
(B) bidentate ligand
(C) ambidentate ligand
(D) hexadentate ligand

15. Which parts of amino acids molecules are linked through hydrogen bonds
in the secondary structure of proteins ?
(A) NH2 group
(B) COOH group
(C) and – NH  groups

(D) None of the above
For questions number 16 to 20, two statements are given  one labelled
Assertion (A) and the other labelled Reason (R). Select the correct
answer to these questions from the codes (i), (ii), (iii) and (iv) as given
below : 15=5

(i) Both Assertion (A) and Reason (R) are correct statements, and
Reason (R) is the correct explanation of the Assertion (A).

(ii) Both Assertion (A) and Reason (R) are correct statements, but
Reason (R) is not the correct explanation of the Assertion (A).

(iii) Assertion (A) is correct, but Reason (R) is incorrect statement.

(iv) Assertion (A) is incorrect, but Reason (R) is correct statement.
16. Assertion (A) : Acetic acid is stronger than formic acid.
Reason (R) : In acetic acid, the electron releasing methyl group makes
it difficult to break the O – H bond.
.56/3/2 7 P.T.O.

17. A{^H$WZ (A) : gmÝÐVm KQ>Zo Ho$ gmW {dÚwV²-AnKQ>ç H$s MmbH$Vm KQ>Vr h¡ &
H$maU (R) : VZwH$aU H$aZo na à{V BH$mB© Am¶VZ ‘| Am¶Zm| H$s g§»¶m ~‹T>Vr h¡ &
18. A{^H$WZ (A) : g§Hw$b [Pt(NH3)4 Cl2]2+ H$s Anojm g§Hw$b [Pt(en)2 Cl2]2+ H$‘
ñWm¶r hmoVm h¡ &
H$maU (R) : g§Hw$b [Pt(en)2 Cl2]2+ H$sboQ> à^md Xem©Vm h¡ &
19. A{^H$WZ (A) : p-‘o{Wbµ’$sZm°b H$s VwbZm ‘| µ’$sZm°b A{YH$ Aåbr¶ h¡ &
H$maU (R) : p-‘o{Wbµ’$sZm°b ‘| Bbo³Q´>m°Z XmVm g‘yh H$s CnpñW{V BgH$mo H$‘ Aåbr¶
H$a XoVr h¡ &
20. A{^H$WZ (A) : namgaU Xm~ EH$ AUwg§»¶ JwUY‘© h¡ &
H$maU (R) : namgaU Xm~ ‘mobaVm Ho$ AZwH«$‘mZwnmVr hmoVm h¡ &
IÊS> I

21. {ZåZ{b{IV H$s ^y{‘H$m {b{IE :
(i) Eobw{‘{Z¶‘ Ho$ {ZîH$f©U ‘| NaAlF4 H$s 1
(ii) Ni Ho$ emoYZ ‘| CO H$s 1
AWdm
~m°³gmBQ> A¶ñH$ Ho$ {ZjmbZ Ûmam ewÕ Eobw{‘Zm àmßV H$aZo go gå~Õ amgm¶{ZH$ g‘rH$aU|
{b{IE & 2

22. Xr JB© A{^{H«$¶m
A + 3B  2C
‘|, C Ho$ ~ZZo H$m doJ 2·5  10–4 mol L–1 s–1 h¡ &
n[aH${bV H$s{OE :
(i) A{^{H«$¶m H$m doJ, Am¡a
(ii) B Ho$ bwßV hmoZo H$m doJ & 2

23. (a) g§Hw$b [CoF6]3 – H$m AmB ¶y nr E gr Zm‘ Am¡a g§H$aU {b{IE &
({X¶m J`m h¡ : Co H$m na‘mUw H«$‘m§H$ = 27)
(b) g§Hw$b [Co(en)2 Cl2]2+ Ûmam {H$g àH$ma H$s g‘md¶dVm Xem©B© OmVr h¡ ? Bg
g§Hw$b Ho$ Cg g‘md¶d H$s g§aMZm H$m Zm‘ {b{IE Omo Y«wdU KyU©H$ hmo & 2
.56/3/2 8

17. Assertion (A) : Conductivity of an electrolyte decreases with decrease in
concentration.
Reason (R) : Number of ions per unit volume increases on dilution.
18. Assertion (A) : [Pt(en)2 Cl2]2+ complex is less stable than
[Pt(NH3)4 Cl2]2+ complex.
Reason (R) : [Pt(en)2 Cl2]2+ complex shows chelate effect.
19. Assertion (A) : Phenol is more acidic than p-methylphenol.
Reason (R) : The presence of an electron releasing group in
p-methylphenol makes it less acidic.
20. Assertion (A) : Osmotic pressure is a colligative property.
Reason (R) : Osmotic pressure is directly proportional to molarity.

SECTION B

21. Write the role of the following :
(i) NaAlF4 in the extraction of Aluminium 1

(ii) CO in the refining of Ni 1
OR
Write the chemical equations involved in the leaching of bauxite ore to
prepare pure alumina. 2

22. In the given reaction
A + 3B  2C,
the rate of formation of C is 2·5  10–4 mol L–1 s–1.
Calculate the
(i) rate of reaction, and
(ii) rate of disappearance of B. 2

23. (a) Write the IUPAC name and hybridisation of the complex [CoF6]3–.
(Given : Atomic number of Co = 27)

(b) What type of isomerism is shown by the complex [Co(en)2 Cl2]2+ ?
Name the structure of an isomer of this complex which is optically
active. 2

.56/3/2 9 P.T.O.

24. ^m¡{VH$ A{YemofU Am¡a agmoemofU Ho$ ~rM Xmo AÝVa {b{IE & 2

AWdm

à˶oH$ Ho$ {bE Cn¶w³V CXmhaU g{hV {ZåZ{b{IV nXm| H$mo n[a^m{fV H$s{OE : 2

(i) ghMmar H$mobm°BS>
(ii) O/W B‘ëeZ (nm¶g)

25. {ZåZ{b{IV A{^{H«$¶m Ho$ CËnmX {b{IE : 1
XeF6 + 2 H2O 
1
³¶m ¶h A{^{H«$¶m aoS>m°³g A{^{H«$¶m h¡ ? XeF6 H$s g§aMZm ~ZmBE & + 1 =1
2 2

26. {ZåZ{b{IV nXm| H$s n[a^mfm {b{IE : 2
(i) ½bmBH$mo{g{S>H$ ~§Y
(ii) àmH¥$V àmoQ>rZ

27. H$maU Xr{OE : 1+1=2

(i) em{IV ûm¥§Ibm dmbo An‘mO©H$m| H$s Anojm Aem{IV ûm¥§Ibm dmbo An‘mO©H$m| H$mo
dar¶Vm Xr OmVr h¡ &
(ii) EñnmQ>}‘ Ja‘ ImZm ~ZmZo Ho$ {bE à¶w³V Zht {H$¶m OmVm h¡ &

IÊS> J

28. {H$gr àW‘ H$mo{Q> H$s A{^{H«$¶m H$mo 40% nyU© hmoZo ‘| 80 {‘ZQ> bJVo h¢ & doJ pñWam§H$ (k)
H$m ‘mZ n[aH${bV H$s{OE & {H$VZo g‘¶ ‘| A{^{H«$¶m 90% nyU© hmoJr ? 3
[ {X`m J`m h¡ : log 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021, log 5 = 0·6771,
log 6 = 0·7782]

.56/3/2 10

24. Write two differences between physisorption and chemisorption. 2

OR

Define the following terms with a suitable example of each : 2

(i) Associated colloids

(ii) O/W emulsion

25. Write the products of the following reaction : 1
XeF6 + 2 H2O 
1 1
Is this reaction a redox reaction ? Draw the structure of XeF6. + =1
2 2

26. Define the following terms : 2

(i) Glycosidic linkage

(ii) Native protein

27. Give reasons : 1+1=2
(i) Unbranched chain detergents are preferred over branched chain
detergents.

(ii) Aspartame is not used in cooking hot dishes.

SECTION C

28. A first order reaction is 40% complete in 80 minutes. Calculate the value
of rate constant (k). In what time will the reaction be 90% completed ? 3

[Given : log 2 = 0·3010, log 3 = 0·4771, log 4 = 0·6021, log 5 = 0·6771,
log 6 = 0·7782]

.56/3/2 11 P.T.O.

29. 298 K na Xr JB© A{^{H«$¶m Ho$ {bE A{YH$V‘ H$m¶© Am¡a log Kc n[aH${bV H$s{OE : 3

Ni (s) + 2 Ag+ (aq)  Ni2+ (aq) + 2 Ag (s)
{X¶m J`m h¡ :
Eo 2  = – 0·25 V, Eo  = + 0·80 V
Ni / Ni Ag / Ag

1 F = 96500 C mol–1

30. {ZåZ{b{IV A{^{H«$¶mAm| Ho$ ‘w»¶ CËnmX/CËnmXm| H$mo {b{IE : 3

31. {ZåZ{b{IV ~hþbH$m| ‘| EH$bH$m| Ho$ Zm‘ Am¡a g§aMZmE± {b{IE : 1+1+1=3
(i) ã¶yZm-N
(ii) àmH¥${VH$ a~a
(iii) ZmBbm°Z-6

32. à˶oH$ Ho$ {bE Cn¶w³V CXmhaU XoH$a Ðd{damJr Am¡a ÐdamJr gm°b H$mo n[a^m{fV H$s{OE &
Ðd{damJr gm°b H$s VwbZm ‘| ÐdamJr gm°b H$m ñH§$XZ H${R>Z ³¶m| hmoVm h¡ ? 3
AWdm
{ZåZ{b{IV nXm| H$mo n[a^m{fV H$s{OE : 3
(i) AmH$ma-daUmË‘H$ CËàoaU
(ii) H«$mâQ> Vmn
(iii) noßQ>Z (noßQ>mBµOoeZ)

.56/3/2 12

29. Calculate the maximum work and log Kc for the given reaction at 298 K : 3

Ni (s) + 2 Ag+ (aq)  Ni2+ (aq) + 2 Ag (s)
Given :
Eo 2  = – 0·25 V, Eo  = + 0·80 V
Ni / Ni Ag / Ag

1 F = 96500 C mol–1

30. Write the major product(s) of the following reactions : 3

31. Write the names and structures of the monomers in the following
polymers : 1+1+1=3
(i) Buna-N
(ii) Natural rubber
(iii) Nylon-6

32. Define Lyophobic and Lyophilic sol with a suitable example of each. Why
is coagulation of Lyophilic sol difficult as compared to Lyophobic sol ? 3
OR
Define the following terms : 3
(i) Shape-selective catalysis
(ii) Kraft temperature
(iii) Peptization

.56/3/2 13 P.T.O.

33. (a) {ZåZ{b{IV A{^{H«$¶m H$s {H«$¶m{d{Y {b{IE :
H
2 CH3CH2OH  CH3CH2OCH2CH3 + H2O
413 K

(b) ³¶y‘rZ go µ\$sZm°b H$m {daMZ {b{IE & 2+1=3
AWdm
Amn {ZåZ{b{IV n[adV©Z H¡$go gånÞ H$a|Jo : 3
(i) gmo{S>¶‘ ’$sZm°³gmBS> go o-hmBS´>mo³gr~oݵOmoBH$ Aåb
(ii) EogrQ>moZ go àmonrZ
(iii) µ\$sZm°b go ³bmoamo~oݵOrZ
34. {Z{‘©V CËnmXm| H$mo {b{IE O~ (CH3)3 C – CHO {ZåZ{b{IV A{^H$‘©H$m| Ho$ gmW
A{^{H«$¶m H$aVm h¡ : 3

(i) VZw NaOH H$s CnpñW{V ‘| CH3COCH3
(ii) HCN
(iii) gmÝÐ NaOH

IÊS> K
35. (a) {H$gr {db¶Z ‘| 5·85 g NaCl (‘moba Ð춑mZ = 58·5 g mol–1) à{V brQ>a
{db¶Z {dÚ‘mZ h¡ & BgH$m 27C na namgaU Xm~ 4·75 dm¶w‘§S>b (atm) h¡ & Bg
{db¶Z ‘| NaCl H$s {d¶moOZ ‘mÌm n[aH${bV H$s{OE & 3
({X¶m J`m h¡ : R = 0·082 L atm K–1 mol–1)
(b) hoZar {Z¶‘ {b{IE & JmoVmImoam| Ûmam à¶w³V dm¶w H$mo hr{b¶‘ go VZwH$aU H$aHo$
Q>¡ÝH$m| ‘| ³¶m| ^am OmVm h¡ ? 1+1
AWdm
(a) F – CH2 – COOH (‘moba Ð춑mZ = 78 g mol–1) Ho$ 19·5 g H$mo 500 g Ob
‘| KmobZo na {h‘m§H$ ‘| 1C H$m AdZ‘Z XoIm J¶m & F – CH2 – COOH H$s
{d¶moOZ ‘mÌm n[aH${bV H$s{OE & 3
[ {X¶m J`m h¡ : Ob Ho$ {bE Kf = 1·86 K kg mol–1]

.56/3/2 14

33. (a) Write the mechanism of the following reaction :
H
2 CH3CH2OH  CH3CH2OCH2CH3 + H2O
413 K

(b) Write the preparation of phenol from cumene. 2+1=3
OR
How can you convert the following : 3
(i) Sodium phenoxide to o-hydroxybenzoic acid
(ii) Acetone to propene
(iii) Phenol to chlorobenzene

34. Write the products formed when (CH3)3 C – CHO reacts with the

following reagents : 3
(i) CH3COCH3 in the presence of dilute NaOH

(ii) HCN

(iii) Conc. NaOH

SECTION D

35. (a) A solution contains 5·85 g NaCl (Molar mass = 58·5 g mol–1) per
litre of solution. It has an osmotic pressure of 4·75 atm at 27C.
Calculate the degree of dissociation of NaCl in this solution. 3
(Given : R = 0·082 L atm K–1 mol–1)

(b) State Henry’s law. Why is air diluted with helium in the tanks
used by scuba divers ? 1+1
OR

(a) When 19·5 g of F – CH2 – COOH (Molar mass = 78 g mol–1) is
dissolved in 500 g of water, the depression in freezing
point is observed to be 1C. Calculate the degree of dissociation of
F – CH2 – COOH. 3
[Given : Kf for water = 1·86 K kg mol–1]
.56/3/2 15 P.T.O.

(b) H$maU Xr{OE :
(i) 0·1 M KCl H$m ³dWZm§H$ 0·1 M ½byH$mog H$s VwbZm ‘| CÀMVa hmoVm h¡ & 1
(ii) bdU {‘bmZo na ‘m§g A{YH$ g‘¶ VH$ n[aa{jV ahVm h¡ & 1

36. (a) H$maU Xr{OE : 3
(i) µOrZm°Z H$s ^m±{V hr{b¶‘ ¶m¡{JH$ Zht ~ZmVr &
(ii) HOCl H$s Anojm HClO4 à~bVa Aåb h¡ &
(iii) J§YH$ EH$ ~hþna‘mUwH$ R>mog h¡ O~{H$ Am°³grOZ {Ûna‘mUwH$ J¡g h¡ &
(b) ¶h Xem©Zo Ho$ {bE {H$ gmÝÐ H2SO4
(i) Am°³grH$maH$, Ed§
(ii) {ZO©bZ H$_©H$ H$s ^m±{V H$m¶© H$aVm h¡,
à˶oH$ Ho$ {bE CXmhaU Ho$ ê$n _| EH$-EH$ A{^{H«$¶m {b{IE & 2
AWdm
(a) {ZåZ{b{IV Ho$ {bE H$maU Xr{OE :
(i) Cl– Am¶Z H$s Anojm F – Am¶Z H$s Ob¶moOZ EÝW¡ënr A{YH$ hmoVr h¡ & 1
(ii) dJ©-16 Ho$ Am°³gmBS>m| ‘| SO2 EH$ AnMm¶H$ h¡, O~{H$ TeO2 EH$
Am°³grH$maH$ h¡ & 1
(b) F2 H$s Ob Ho$ gmW A{^{H«$¶m {b{IE & Am¶moS>rZ (I2) Ob Ho$ gmW A{^{H«$¶m
³¶m| Zht H$aVr ? 1+1
(c) XeF2 H$s g§aMZm ~ZmBE & 1

37. (a) H$maU Xr{OE : 3

(i) ¶Ú{n  NH2 g‘yh Bbo³Q´>m°ZamJr à{VñWmnZ A{^{H«$¶mAm| ‘| Am°Wm} Ed§
n¡am {ZX}eH$ hmoVm h¡ {’$a ^r Eo{ZbrZ ZmBQ´>moH$aU Ûmam ¶WoîQ> _mÌm ‘|
‘oQ>m-ZmBQ´>moEo{ZbrZ XoVr h¡ &
(ii) Obr¶ {db¶Z ‘| (CH3)3 N H$s Anojm (CH3)2 NH A{YH$ jmaH$s¶
hmoVm h¡ &
(iii) ewÕ àmW{‘H$ Eo‘rZm| Ho$ {daMZ Ho$ {bE EopëH$b h¡bmBS>m| H$m
Eo‘moZr-AnKQ>Z EH$ AÀN>r {d{Y Zht h¡ &

.56/3/2 16

(b) Give reasons :
(i) 0·1 M KCl has higher boiling point than 0·1 M Glucose. 1
(ii) Meat is preserved for a longer time by salting. 1

36. (a) Give reasons : 3

(i) Helium does not form compounds like Xenon.
(ii) HClO4 is a stronger acid than HOCl.

(iii) Sulphur is a polyatomic solid whereas Oxygen is a diatomic
gas.

(b) Write one reaction as an example of each, to show that
conc. H2SO4 acts as

(i) an oxidising agent, and

(ii) a dehydrating agent. 2
OR
(a) Account for the following :

(i) Hydration enthalpy of F – ion is more than Cl – ion. 1
(ii) SO2 is a reducing agent, whereas TeO2 is an oxidising agent
in group-16 oxides. 1
(b) Write the reaction of F2 with water. Why does I2 not react with
water ? 1+1
(c) Draw the structure of XeF2. 1

37. (a) Give reasons : 3
(i) Although – NH2 group is o/p directing in electrophilic
substitution reactions, yet aniline, on nitration gives good
yield of m-nitroaniline.
(ii) (CH3)2 NH is more basic than (CH3)3 N in an aqueous
solution.
(iii) Ammonolysis of alkyl halides is not a good method to
prepare pure primary amines.

.56/3/2 17 P.T.O.

(b) {ZåZ{b{IV Ho$ ‘ܶ {d^oX H$s{OE : 2

(i) CH3CH2NH2 Am¡a (CH3CH2)2 NH

(ii) Eo{ZbrZ Am¡a CH3NH2
AWdm
(a) {ZåZ{b{IV A{^{H«$¶mAm| ‘| A Am¡a B H$s g§aMZmE± {b{IE :
CuCN H O /H
(i) C6H5 N 2 Cl–  A 2  B 1

NH3 NaOBr
(ii) CH3COOH   A  B 1


(b) ‘o{Wb Eo_rZ H$s ~oݵOm°¶b ³bmoamBS> Ho$ gmW amgm¶{ZH$ A{^{H«$¶m {b{IE Am¡a
àmßV CËnmX H$m AmB ¶y nr E gr Zm‘ {b{IE & 1+1

(c) {ZåZ{b{IV H$mo CZHo$ pKb ‘mZm| Ho$ ~‹T>Vo hþE H«$‘ ‘| ì¶dpñWV H$s{OE : 1
C6H5NH2, NH3, C2H5NH2, (C2H5)2 NH

.56/3/2 18

(b) Distinguish between the following : 2
(i) CH3CH2NH2 and (CH3CH2)2 NH

(ii) Aniline and CH3NH2

OR

(a) Write the structures of A and B in the following reactions :

 – CuCN H 2O / H 
(i) C6H5 N 2 Cl  A   B 1

NH3 NaOBr
(ii) CH3COOH   A  B 1


(b) Write the chemical reaction of methyl amine with benzoyl chloride
and write the IUPAC name of the product obtained. 1+1

(c) Arrange the following in the increasing order of their pKb values : 1
C6H5NH2, NH3, C2H5NH2, (C2H5)2 NH

.56/3/2 19 P.T.O.