CBSE Class 12 Chemistry Question Paper 2020 Set 56-1-3

H$moS> Z§.
Code No. 56/1/3
amob Z§. narjmWu H$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
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n¥ð> 19 h¢ & paper contains 19 printed pages.

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(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.
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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

.56/1/3 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

EopëH$b h¡bmBS>m| H$s à{VñWmnZ A{^{H«$`m _w»`V`m SN1 AWdm SN2 {H«$`m{d{Y Ûmam
hmoVr h¡ & à{VñWmnZ A{^{H«$`mE± hmoZo Ho$ {bE EopëH$b h¡bmBS> {H$gr ^r {H«$`m{d{Y H$mo
AnZmE±, CZHo$ {bE H$m~©Z h¡bmoOZ Am~ÝY H$s Y«wdUVm hr CÎmaXm`r hmoVr h¡ & SN1
A{^{H«$`mAm| H$m doJ H$m~m}H¡$Q>m`Z Ho$ ñWm{`Ëd na {Z^©a H$aVm h¡ O~{H$ SN2
A{^{H«$`mAm| H$m {Ì{d_{dÝ`mg H$maH$ na & `{X Amapå^H$ nXmW© {H$aob `m¡{JH$ hmo, Vmo
CËnmX `m Vmo à{Vbmo{_V hmoJm AWdm ao{g{_H$ {_lU, Omo EopëH$b h¡bmBS>m| Ûmam AnZmB© JB©
{H«$`m{d{Y Ho$ àH$ma na {Z^©a H$aVm h¡ & B©Wam| H$m HI go {dXbZ ^r {Ì{d_{dÝ`mg H$maH$
Am¡a H$m~m}H¡$Q>m`Z Ho$ ñWm{`Ëd go {Z`pÝÌV hmoVm h¡, Omo Bg ~mV H$m ÚmoVH$ h¡ {H$ H$m~©{ZH$
agm`Z _| `hr Xmo à_wI H$maH$ h¢ Omo h_| ghm`Vm H$aVo h¢ {H$ CËnmX {H$g àH$ma H$m
~ZoJm ?
.56/1/3 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 substitution reaction of alkyl halide mainly occurs by SN1 or SN2
mechanism. Whatever mechanism alkyl halides follow for the
substitution reaction to occur, the polarity of the carbon halogen bond is
responsible for these substitution reactions. The rate of SN1 reactions are
governed by the stability of carbocation whereas for SN2 reactions steric
factor is the deciding factor. If the starting material is a chiral compound,
we may end up with an inverted product or racemic mixture depending
upon the type of mechanism followed by alkyl halide. Cleavage of ethers
with HI is also governed by steric factor and stability of carbocation,
which indicates that in organic chemistry, these two major factors help
us in deciding the kind of product formed.

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

1. ~ZZo dmbo CËnmX H$s {Ì{d_agm`Z H$s àmJw{º$ H$s{OE `{X H$moB© Y«wdU KyU©H$ (àH$meV:
g{H«$`) EopëH$b h¡bmBS> SN1 {H«$`m{d{Y go à{VñWmnZ A{^{H«$`m gånÞ H$aVm h¡ &
2. g_Vb-Y«w{dV àH$me Š`m h¡ ?
3. ~ZZo dmbo CËnmXm| H$s g§aMZmE± {b{IE O~ EWm°Šgr~oݵOrZ H$mo HI Ho$ gmW A{^{H«${`V
{H$`m OmVm h¡ &
4. _w»` CËnmX H$s àmJw{º$ H$s{OE O~ 2-~«mo_monoÝQ>oZ, EoëH$mohm°br KOH Ho$ gmW A{^{H«$`m
H$aVm h¡ &
5. CHI3 H$m EH$ Cn`moJ Xr{OE &

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

6. `{X Ðd A Am¡a B Ho$ ŠdWZm§H$ $H«$_e: 140C Am¡a 180C h¢, Vmo Cg Ðd H$s nhMmZ
H$s{OE {OgH$m 90C na dmîn Xm~ {ZåZVa hmoJm &
7. {H$gr An_mO©H$ _| CnpñWV H$m¡Z-gr g§aMZmË_H$ BH$mB© CgH$mo AO¡d{ZåZrH$aUr` ~Zm XoVr
h¡ ?
8. Q>oâbm°Z Ho$ EH$bH$ H$s g§aMZm Xr{OE &
9. bmoho H$s dñVwAm| H$mo gwa{jV aIZo Ho$ {bE qµOH$ VWm {Q>Z _| go {H$gH$s H$moqQ>J ~ohVa h¡ ?
10. Š`m {H$gr A{^{H«$`m H$m doJ pñWam§H$ T na {Z^©a H$aoJm `{X A{^{H«$`m H$s Eact (g{H«$`U
D$Om©) eyÝ` hmo ?
àíZ g§»`m 11 go 15 ~hþ{dH$ënr¶ àíZ h¢ : 15=5
11. {XE JE `m¡{JH$ H$m ghr AmB©.`y.nr.E.gr. Zm_ Š`m h¡ ?

(A) 2,2-S>mB_o{Wbã`yQ>oZm°BH$ Aåb
(B) 2-H$m~m}pŠgb-2-_o{Wbã`yQ>Z
o
(C) 2-Eo{Wb-2-_o{WbàmonoZm°BH$ Aåb
(D) 3-_o{Wbã`yQ>oZ H$m~m}pŠg{bH$ Aåb

.56/1/3 4

1. Predict the stereochemistry of the product formed if an optically active
alkyl halide undergoes substitution reaction by SN1 mechanism.

2. What is plane polarised light ?

3. Write the structures of the products formed when ethoxybenzene is
treated with HI.

4. Predict the major product formed when 2-Bromopentane reacts with
alcoholic KOH.
5. Give one use of CHI3.

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

6. Identify which liquid will have lower vapour pressure at 90C if the
boiling points of two liquids A and B are 140C and 180C respectively.

7. Which structural unit present in a detergent makes it non-biodegradable ?

8. Give the structure of the monomer of Teflon.

9. Out of zinc and tin, whose coating is better to protect iron objects ?

10. Will the rate constant of the reaction depend upon T if the Eact
(activation energy) of the reaction is zero ?

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

11. What is the correct IUPAC name of the given compound ?

(A) 2,2-Dimethylbutanoic acid
(B) 2-Carboxyl-2-methylbutane
(C) 2-Ethyl-2-methylpropanoic acid
(D) 3-Methylbutane carboxylic acid
.56/1/3 5 P.T.O.

12. M_© g§ñH$aU CÚmoJ _| M_© H$m H$R>moa hmoZm {Z^©a H$aVm h¡
(A) d¡ÚwV H$U-g§MbZ na
(B) {dÚwV²-namgaU na
(C) nmañn[aH$ ñH§$XZ na
(D) {Q>ÝS>b à^md na

13. Obr` {db`Z _| {ZåZ{b{IV _| go à~bV_ jma h¡
(A) _o{WbEo_rZ
(B) S>mB_o{WbEo_rZ
(C) Q´>mB_o{WbEo_rZ
(D) Eo{ZbrZ

14. Am`moS>mo\$m°_© narjU {H$gHo$ Ûmam {X`m OmVm h¡ ?
(A) noÝQ>oZ-2-AmoZ
(B) EWoZm°BH$ Aåb
(C) noÝQ>oZ-3-AmoZ
(D) _oWm°Šgr_oWoZ

15. {ZåZ{b{IV g§H«$_U VÎdm| _| go {H$gHo$ Ûmam A{YH$V_ Am°ŠgrH$aU AdñWmE± àX{e©V H$s
OmVr h¢ ?
(A) Sc (Z = 21)

(B) Cr (Z = 24)

(C) Mn (Z = 25)

(D) Fe (Z = 26)

.56/1/3 6

12. Hardening of leather in tanning industry is based on

(A) Electrophoresis

(B) Electro-osmosis

(C) Mutual coagulation

(D) Tyndall effect

13. Out of the following, the strongest base in aqueous solution is

(A) Methylamine

(B) Dimethylamine

(C) Trimethylamine

(D) Aniline

14. Iodoform test is given by

(A) Pentan-2-one

(B) Ethanoic acid

(C) Pentan-3-one

(D) Methoxymethane

15. Out of the following transition elements, the maximum number of
oxidation states are shown by

(A) Sc (Z = 21)

(B) Cr (Z = 24)

(C) Mn (Z = 25)

(D) Fe (Z = 26)

.56/1/3 7 P.T.O.

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$WZ (A) : A{^{H«$`m H2 + Br2  2HBr _| AmpÊdH$Vm 2 àVrV hmoVr h¡ &
H$maU (R) : Xr hþB© àmW{_H$ A{^{H«$`m _| A{^H$maH$m| Ho$ Xmo AUw ^mJ boVo h¢ &
17. A{^H$WZ (A) : Cnghg§`moOZ `m¡{JH$m| _| C^`X§Vr g§b½Zr Ho$ H$maU ~ÝYZr g_md`dVm
CËnÞ hmoVr h¡ &
H$maU (R) : C^`X§Vr g§b½Zr O¡go NO2 _| Xmo {^Þ XmVm na_mUw N Am¡a O hmoVo h¢ &
18. A{^H$WZ (A) : Au Am¡a Ag H$m {ZîH$f©U CZHo$ A`ñH$m| Ho$ NaCN Ho$ VZw {db`Z Ûmam
{ZjmbZ go {H$`m OmVm h¡ &
H$maU (R) : BZ A`ñH$m| go g§~Õ Aew{Õ`m± NaCN _| Kwb OmVr h¢ &
19. A{^H$WZ (A) : F2 AUw _| F – F Am~ÝY Xþ~©b hmoVm h¡ &
H$maU (R) : F na_mUw H$m AmH$ma N>moQ>m hmoVm h¡ &

20. A{^H$WZ (A) : gyH«$mog EH$ AZnM`r eH©$am h¡ &
H$maU (R) : ½byH$mog VWm \«$ŠQ>moµO Ho$ AnMm`H$ g_yh ½bmBH$mo{g{S>H$ Am~§Y {Z_m©U _|
à`wº$ hmoVo h¢ &

IÊS> I

21. 300 K na `y[a`m (‘moba Ð춑mZ = 60 g/mol) Ho$ 5% {db`Z H$m namgaU Xm~
n[aH${bV H$s{OE & [R = 0·0821 L atm K–1 mol–1] 2

AWdm
.56/1/3 8

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) : The molecularity of the reaction H2 + Br2  2HBr
appears to be 2.
Reason (R) : Two molecules of the reactants are involved in the given
elementary reaction.

17. Assertion (A) : Linkage isomerism arises in coordination compounds
because of ambidentate ligand.
Reason (R) : Ambidentate ligand like NO2 has two different donor
atoms i.e., N and O.

18. Assertion (A) : Au and Ag are extracted by leaching their ores with a dil.
solution of NaCN.
Reason (R) : Impurities associated with these ores dissolve in NaCN.

19. Assertion (A) : F – F bond in F2 molecule is weak.
Reason (R) : F atom is small in size.

20. Assertion (A) : Sucrose is a non-reducing sugar.
Reason (R) : Reducing groups of glucose and fructose are involved in
glycosidic bond formation.

SECTION B

21. For a 5% solution of urea (Molar mass = 60 g/mol), calculate the osmotic
pressure at 300 K. [R = 0·0821 L atm K–1 mol–1] 2
OR
.56/1/3 9 P.T.O.

{dem Zo Xmo Obr` {db`Z, EH$ _| 100 g Ob _| `y[a`m (‘moba Ð춑mZ = 60 g/mol) Ho$
7·5 g Am¡a Xÿgao _| {H$gr nXmW© Z Ho$ 42·75 g, 100 g Ob _| {bE & `h ào{jV {H$`m
J`m {H$ XmoZm| {db`Z EH$g_mZ Vmn na {h_r^yV hþE & Z H$m _moba Ðì`_mZ n[aH${bV
H$s{OE & 2

22. A{^H$maH$ H$s gmÝÐVm Am¡a g_` Ho$ ~rM {XE JE J«m\$ H$m {díbofU H$s{OE & 12=2

(a) A{^{H«$`m H$s H$mo{Q> H$s àmJw{º$ H$s{OE &>
(b) g¡ÕmpÝVH$ Ñ{ï> go Š`m AZ§VH$mb Ho$ ~mX {H$gr A{^H$maH$ H$s gmÝÐVm KQ>H$a eyÝ`
hmo gH$Vr h¡ ? ì`m»`m H$s{OE &

23. {ZåZ{b{IV nXm| H$s n[a^mfm {b{IE : 12=2

(a) àem§VH$
(b) ny{VamoYr
AWdm
gm~wZm| H$s emoYZ {H«$`m g_PmBE & 2

.56/1/3 10

Visha took two aqueous solutions — one containing 7·5 g of urea (Molar
mass = 60 g/mol) and the other containing 42·75 g of substance Z in
100 g of water, respectively. It was observed that both the solutions froze
at the same temperature. Calculate the molar mass of Z. 2

22. Analyse the given graph, drawn between concentration of reactant vs.
time. 12=2

(a) Predict the order of reaction.

(b) Theoretically, can the concentration of the reactant reduce to zero
after infinite time ? Explain.

23. Define the following terms : 12=2

(a) Tranquilizers

(b) Antiseptic

OR

Explain the cleansing action of soaps. 2

.56/1/3 11 P.T.O.

24. {ZåZ{b{IV ~hþbH$m| _| EH$bH$m| Ho$ Zm_ Am¡a g§aMZmE± {b{IE : 12=2

(a) ã`yZm-N
(b) ZmBbm°Z 6
25. {ZåZ{b{IV AUwAm| H$s AmH¥${V It{ME : 12=2

(a) H2S2O8>

(b) XeF2

26. {ZåZ{b{IV `m¡{JH$m| Ho$ gyÌ Xr{OE : 12=2

(a) noÝQ>mEoå_rZH$m~m}ZoQ>moH$mo~mëQ> (III) ŠbmoamBS> >
(b) nmoQ>¡{e`_ Q>oQ´>mgm`{ZS>mo{ZH¡$boQ> (II)

27. Š`m hmoVm h¡ O~
(a) EogrQ>moZ H$mo Zn(Hg) / gmÝÐ HCl Ho$ gmW A{^{H«${`V {H$`m OmVm h¡, Am¡a
(b) EWoZ¡b H$mo _o{Wb_¡½Zr{e`_ ~«mo_mBS> Ho$ gmW A{^{H«${`V H$aHo$ Ob-AnK{Q>V
{H$`m OmVm h¡ ? 12=2

IÊS> J
28. {ZåZ{b{IV Ho$ H$maU Xr{OE : 13=3

(a) gëâ`yag Aåb EH$ AnMm`H$ h¡ &
(b) âbwAmoarZ Ho$db EH$ Am°ŠgmoAåb ~ZmVr h¡ &
(c) CËH¥$îQ> J¡gm| Ho$ ŠdWZm§H$ He go Rn VH$ ~‹T>Vo h¢ &>
AWdm
{ZåZ{b{IV amgm`{ZH$ A{^{H«$`mAm| H$mo nyU© H$s{OE : 13=3

(a) MnO2 + 4 HCl 
(b) XeF6 + KF 
(c) I – (aq) + H+ (aq) + O (g) 2

.56/1/3 12

24. Write the names and structures of monomers in the following polymers :
12=2
(a) Buna-N
(b) Nylon 6

25. Draw the shape of the following molecules : 12=2
(a) H2S2O8
(b) XeF2

26. Give the formulae of the following compounds : 12=2
(a) Pentaamminecarbonatocobalt (III) chloride
(b) Potassium tetracyanidonickelate (II)

27. What happens when
(a) Acetone is treated with Zn(Hg) / Conc. HCl, and
(b) Ethanal is treated with methylmagnesium bromide and then
hydrolysed ? 12=2

SECTION C

28. Account for the following : 13=3
(a) Sulphurous acid is a reducing agent.
(b) Fluorine forms only one oxoacid.
(c) Boiling point of noble gases increases from He to Rn.
OR
Complete the following chemical reactions : 13=3

(a) MnO2 + 4 HCl 

(b) XeF6 + KF 

(c) I – (aq) + H+ (aq) + O2 (g) 

.56/1/3 13 P.T.O.

29. 75 g Eogr{Q>H$ Aåb _| Kmobo OmZo dmbr EoñH$m°{~©H$ Aåb

(‘moba Ð춑mZ = 176 g mol–1) H$s _mÌm (Ðì`_mZ) n[aH${bV H$s{OE {Oggo BgH$m
{h_m§H$ 1·5C H$_ hmo OmE & (Kf = 3·9 K kg mol–1) 3

30. A{^{H«$¶m H$m doJ {H$g àH$ma à^m{dV hmoJm O~
(a) A{^H$maH$ H$m n¥îR>r` joÌ\$b H$_ H$a {X`m OmE,
(b) CËH«$_Ur` A{^{H«$`m _| CËàoaH$ {_bm {X`m OmE, Am¡a
(c) A{^{H«$`m H$m Vmn ~‹T>m {X`m OmE ? 13=3

1
31. {ZåZ{b{IV A{^{H«$`mAm| Ho$ AZwH«$_ _| A Am¡a B H$s g§aMZmE± Xr{OE : 6=3
2
NH3 NaOBr
(a) CH3COOH   A  B


Fe / HCl NaNO  HCl
(b) C6H5NO2  A  2  B
0 –5C

+ CuCN H2O / H
(c) C6H5N2Cl    A    B


AWdm
(a) {ZåZ{b{IV `wJbm| Ho$ `m¡{JH$m| Ho$ ~rM Amn {d^oX H¡$go H$a|Jo : 12=2

(i) Eo{ZbrZ Am¡a EWoZo_rZ
(ii) Eo{ZbrZ Am¡a N-_o{WbEo{ZbrZ
(b) {ZåZ{b{IV `m¡{JH$m| H$mo CZHo$ ŠdWZm§H$ Ho$ KQ>Vo hþE H«$_ _| ì`dpñWV H$s{OE : 1
ã`yQ>oZm°b, ã`yQ>oZo_rZ, ã`yQ>oZ

32. {ZåZ{b{IV Ho$ {bE {dídgZr` ñnîQ>rH$aU Xr{OE : 13=3
(a) ½byH$mog 2,4-S>r.EZ.nr. narjU Zht XoVm &
(b) DNA Ho$ Xmo aÁOwH$ g_mZ Zht hmoVo, naÝVw EH$-Xÿgao Ho$ nyaH$ hmoVo h¢ &
(c) ñQ>mM© Am¡a gobwbmog XmoZm| _| EH$bH$m| Ho$ ê$n _| ½byH$mog BH$mB© hmoVr h¡ , {\$a ^r do
g§aMZmË_H$ Ñ{îQ> go {^Þ h¢ &
.56/1/3 14

29. Calculate the mass of ascorbic acid (Molar mass = 176 g mol–1) to be
dissolved in 75 g of acetic acid, to lower its freezing point by 1·5C.
(Kf = 3·9 K kg mol–1) 3

30. How will the rate of the reaction be affected when
(a) Surface area of the reactant is reduced,
(b) Catalyst is added in a reversible reaction, and

(c) Temperature of the reaction is increased ? 13=3

1
31. Give the structures of A and B in the following sequence of reactions : 6=3
2
NH3 NaOBr
(a) CH3COOH   A  B

Fe / HCl NaNO  HCl
(b) C6H5NO2  A  2  B
0 –5C

CuCN H O / H
C6H5N2Cl    A 2 
+
(c)  B


OR

(a) How will you distinguish between the following pairs of
compounds : 12=2
(i) Aniline and Ethanamine
(ii) Aniline and N-methylaniline

(b) Arrange the following compounds in decreasing order of their
boiling points : 1
Butanol, Butanamine, Butane

32. Give the plausible explanation for the following : 13=3
(a) Glucose doesn’t give 2,4-DNP test.
(b) The two strands in DNA are not identical but are complementary.
(c) Starch and cellulose both contain glucose unit as monomer, yet
they are structurally different.

.56/1/3 15 P.T.O.

33. {ZåZ{b{IV H$s ^y{_H$m ñnîQ> H$s{OE : 13=3

(a) \o$Z ßbdZ àH«$_ _| NaCN H$s &
(b) Zr Ho$ YmVwH$_© _| I2 H$s &

(c) Fe Ho$ YmVwH$_© _| MyZm-nËWa H$s &

34. {ZåZ{b{IV Ho$ AmYma na ^m¡{VH$ A{YemofU Am¡a agmodemofU _| {d^oX H$s{OE :
(a) AmH$f©U ~b,
(b) Vmn, Am¡a
(c) A{YemofU H$s EÝW¡ënr & 13=3

IÊS> K
35. (a) {ZåZ{b{IV Ho$ H$maU {b{IE : 13=3

(i) H$m°na (I) `m¡{JH$ g\o$X hmoVo h¢ O~{H$ H$m°na (II) `m¡{JH$ a§JrZ hmoVo h¢ &
(ii) H«$mo_oQ> AnZm a§J Aåbr` {db`Z _| n[ad{V©V H$a XoVo h¢ &
(iii) Zn, Cd, Hg d-ãbm°H$ VÎd Vmo _mZo OmVo h¢ naÝVw g§H«$_U VÎd Zht &

(b) Co Am¡a Co2+ Ho$ BboŠQ´>m°{ZH$ {dÝ`mg {bIH$a Co2+ (Z = 27) Ho$ {bE
àMH«$U-_mÌ AmKyU© n[aH${bV H$s{OE & 2

AWdm
(a) b¡ÝWoZm°`S>m| Am¡a EopŠQ>Zm°`S>m| Ho$ _Ü` A§Va Ho$ VrZ {~ÝXþ Xr{OE & 3

(b) H$maU XoVo hþE EH$ na_mUw/Am`Z N>m±{Q>E Omo nyN>m J`m JwUY_© Xem©Vm hmo : 12=2

(i) Sc3+ AWdm Cr3+ (à{VMwå~H$s` ì`dhma Xem©Vm h¡)

(ii) Cr AWdm Cu (Cƒ JbZm§H$ Am¡a ŠdWZm§H$)

36. (a) t-ã`y{Q>b EoëH$mohm°b Am¡a n-ã`yQ>oZm°b _| go H$m¡Z-gm Aåb CËào[aV {ZO©bZ Vrd«Vm go
XoJm Am¡a Š`m| ? 2

.56/1/3 16

33. Explain the role of the following : 13=3

(a) NaCN in froth floatation process.

(b) I2 in the metallurgy of Zr.

(c) Limestone in the metallurgy of Fe.

34. Distinguish between physisorption and chemisorption on the basis of

(a) Force of attraction,

(b) Temperature, and
(c) Enthalpy of adsorption. 13=3

SECTION D

35. (a) Account for the following : 13=3
(i) Copper (I) compounds are white whereas Copper (II)
compounds are coloured.
(ii) Chromates change their colour when kept in an acidic
solution.
(iii) Zn, Cd, Hg are considered as d-block elements but not as
transition elements.

(b) Calculate the spin-only moment of Co2+ (Z = 27) by writing the
electronic configuration of Co and Co2+. 2
OR

(a) Give three points of difference between lanthanoids and actinoids. 3
(b) Give reason and select one atom/ion which will exhibit asked
property : 12=2

(i) Sc3+ or Cr3+ (Exhibit diamagnetic behaviour)
(ii) Cr or Cu (High melting and boiling point)

36. (a) Out of t-butyl alcohol and n-butanol, which one will undergo acid
catalyzed dehydration faster and why ? 2

.56/1/3 17 P.T.O.

(b) {ZåZ{b{IV ê$nmÝVaU gånÞ H$s{OE : 13=3
(i) µ\$sZm°b go g¡{b{gbEopëS>hmBS>
(ii) t-ã`y{Q>bŠbmoamBS> go t-ã`y{Q>b E{Wb B©Wa
(iii) àmonrZ go àmonoZm°b
AWdm
(a) EWrZ go EWoZm°b ~ZZo H$s {H«$`m{d{Y Xr{OE & 2

(b) {ZåZ{b{IV ê$nm§VaU gånÞ H$aZo Ho$ {bE A{^H$_©H$ H$s àmJw{º$ H$s{OE : 13=3
(i) µ\$sZm°b go ~oݵOmo{ŠdZmoZ
(ii) Eo{Zgmob go p-~«mo_moEo{Zgmob
(iii) µ\$sZm°b go 2,4,6-Q´>mB~«mo_moµ\$sZm°b

37. (a) A{^{H«$¶m
Zn (s) + Cu2+ (aq)  Zn2+ (aq) + Cu (s)
Ho$ {bE G n[aH${bV H$s{OE & 3
{X`m J`m h¡ : Zn2+/Zn Ho$ {bE E = – 0·76 V
Cu2+/Cu Ho$ {bE E = + 0·34 V
R = 8·314 JK–1 mol–1
F = 96500 C mol–1.
(b) BªYZ gobm| Ho$ Xmo bm^ Xr{OE & 2
AWdm
(a) {ZåZ{b{IV `wJbm| _| go, H$maU g{hV Cg EH$ H$s àmJw{º$ H$s{OE Omo {dÚwV² Ymam
H$s A{YH$ _mÌm Ho$ MmbZ H$s AZw_{V XoVm h¡ : 3
(i) 30C na Mm±Xr H$m Vma AWdm 60C na Mm±Xr H$m Vma &
(ii) 0·1 M CH3COOH {db`Z AWdm 1 M CH3COOH {db`Z &
(iii) 20C na KCl {db`Z AWdm 50C na KCl {db`Z &

(b) {dÚwV²-amgm`{ZH$ gob Am¡a {dÚwV²-AnKQ>Zr gob Ho$ _Ü` A§Va Ho$ Xmo {~ÝXþ Xr{OE & 2

.56/1/3 18

(b) Carry out the following conversions : 13=3
(i) Phenol to Salicylaldehyde
(ii) t-butylchloride to t-butyl ethyl ether
(iii) Propene to Propanol

OR

(a) Give the mechanism for the formation of ethanol from ethene. 2

(b) Predict the reagent for carrying out the following conversions : 13=3
(i) Phenol to benzoquinone
(ii) Anisole to p-bromoanisole
(iii) Phenol to 2,4,6-tribromophenol

37. (a) Calculate G for the reaction

Zn (s) + Cu2+ (aq)  Zn2+ (aq) + Cu (s). 3
Given : E for Zn2+/Zn = – 0·76 V and
E for Cu2+/Cu = + 0·34 V
R = 8·314 JK–1 mol–1
F = 96500 C mol–1.

(b) Give two advantages of fuel cells. 2
OR
(a) Out of the following pairs, predict with reason which pair will
allow greater conduction of electricity : 3
(i) Silver wire at 30C or silver wire at 60C.
(ii) 0·1 M CH3COOH solution or 1 M CH3COOH solution.
(iii) KCl solution at 20C or KCl solution at 50C.

(b) Give two points of differences between electrochemical and
electrolytic cells. 2

.56/1/3 19 P.T.O.