AHSEC HS 2nd Year Question Paper 2022 Chemistry

Total nunfuer of pages - 16

32T CHEM

2022
CHEIVflSTRY
(Theory)

Full Marks: 70
Pass Marks : 21

Time : Three hours

The figures in the margin indicate full marks
for the questions.
General Instructions :
(i) All questions are contpulsory..
(ii) Marks for ench question are indicated agninst it.
(iii) Ansttters sltould be specific nnd to tlrc point.
At,) Questiort nunrbers '1. to I cottsist of eight uery slrcrt
anszLter type questions and cnrry 1 nmrk eaclt. 1x8 = 8
(t) Question nwubers 9 to 16 cortsist of ten short artsruer
type questions and avry 2 nmrks eaclu 2xlO = 20
(t'i) Qtrcstion nurubers 77 to 25 consist of nine slnrt nnstter
type questions nrul carry 3 mnrks ench. 3x9 = 27
(air) Question numbers 26 to 28 consist of three long anxoer
. type questions and cnrry 5 marks each. 5x3 = 15
Total = 70

Contd.

A metal crystallises in a body-centred cubic structure. lf'n' is the edge
length of its unit cell,'r' is the radius of the sphere, what is the relationship
between ' r' and 'n' z 1'

eB W.iQsrsk-s r{fi{ c{Eq^r- Ttrfs ql t <fr em cfllz6r a1ffi'a'q
ut+ 6afl-aafi;q <IFTtii'r' €, (g(S 'n' 9l$ 'r'{ Tlqo {'r'6 fr q<?
"lflt.I

Arrange the following compounds in the increasing order of their boiling
points :

EEE ErflF1g dflr+t6 Uwli+ \tr$-ft Etrslio Tcs?f{t s

CHz
- CHO, CH3
- CHz
- OH, CH: - CHz-CHz

write down the f ormula of Tetraamineaquachloridocobalt(III) chloride.

ffite{R{eTffi'Fs'€rs (lll) s\trs< ltfl
qir+s fr.ll t

Write the IUPAC name'of the following compound:

qqs fifl ffi1d< IUPAC 41r fr?il s

: CH - CH2- oH
ill
",,\,tt'
\/

5. What will be the impact on Krr when the molality of a solution is dorrul"d I
1,

qbt E{< nttr'G'F Esct <Urd K,.< s4<ls ft aq< qR<t

32T CHEM l2l

rE

6. Which is a stronger oxidizing agent - Bl(2,) or 5ll(z)? 'l

Bi(u)ga sb(zr<&s<E csl-dttl (<& tffiqt++u-<l'E{?

7. pK6 of aniline. is more than that of methylamine. Why ?
fiqEEe{E{< Wilvqfrfr{< pK6( nFr ftr mRqlr

8. Which of the foliowing compounds can undergo Hell-Volhard-Zelinsky
-l
reaction ?

EEs fifl mrdlt ffirR cqq-vbRd-crfr{fr cq={{l{?

O Benzoic acid
' mqqfr-s eFs

(ii) Propanoic acid
a{rafr+ qfis

9. The freezing point depression constant for water is 1'86'C rl-1 . If 5 0g of
Nn2SOa is dissolved in 45g of water, then freezing point is changed by
3.80'C. Calculate the Van't Hoff factor for Nn2SOa. 2

qffitr{ g<lsr $q ?qcq t.86"Cnt-1r <fr +sg "ttfrs stl8 Nn2Soa
"fft< furio
qaYs cl q-{, Nrs R*tio : so"c r{ w<4fr8 E{ I qfu{t Nnzsor-< <l-(< cst
qT eq-G m fr"fi o{ r

oR/ q?lfil

Stqte Henry's law. Why do gases nearly always tend to be less soluble in
iiquids as the temperature is raised ? 2

6sA< 1ocilErmq<<l lErcel 1fr ccq ctl{c<Frc,itr s-{osfr{q&sr {Fftq
EAPtr q{?

32T CHEM t3l Conttl.

10. Calculate the pH ai which the potential of hydrogen electrode will be
0.059 Y. 2

qRgtqa frWqar< fi-s<< qF 0.059 v q'rq pH $a FurF < fi'fu mt r

oR/q?F{l

The chemistry of corrosion of iron is essentially an electrochemical
phenomenon. Explain the rbactions occurring during the corrosion of iron
in the atmosphere. 2

qkt< qa er< <qwarat 1avs,{s F1ls<lcl-{frs qR6+ r qE qEsqr sr c<t'<K
rr'{v <l{{eqs c(qfre Rfu{lC<I< <fl?l]l ffil

11,. Why H2 and 02 do not react at room temperature ? Write the rate equation
for the reaction A, + 38,, -'> 2C , if the overall order of the reaction is zero.
1+'l=2

HzYl$ oz c{ T5F sl"FllqlE fr{ frfu1il aq6qr A, +3F,"-+ 2C frffi6
sFr"i rfG F-rtl fi?l] sfr[q {n{ kffii W @-d< qI I

oR/qqEl

A first order reaction has a rate constant of 0'0051lrir-]. If we begin with
0.10M concerrtration of the reactant, what concentration of reactant will
remain in solution after 3 lrours ? 2

.sB aqn em Rfuar< riG :w< qta ?acq 0'0051frF8-r | {fr qfi 0'10M
fifuTc riluqrs qt+e sr.<t, csrc GF q$< qlw E<lfu Firyn eEot< Rfur+
qtft<?

32T CHEM t4l

12. Answer afly ttoo :

fre 1rqt fAEUe< frrn I

(n) Write the mathematical expression for the Freuncllich adsorption

isotherm and draw the graPh logl vs logP. 2
a

ffiFe<qkc.fl{qcrql€< ritff&sc'ft-fi.l(il fr?ltqr$ bg L vs bg P4
a

6fi q(GI Fttl

(b) How rlo emulsifiers stabilize emulsion ? Name koo emulsifiers' .2
w<Eftr Sc$ cTr+f$ q<u-fi 1fu or<r fAq<EA{ qr-q
qn G'qt

(c) Define shape-selective catalysis. Give an example' 1.+L=2

qTC fr{Fi-s{ \tr{fi frfu< c<el G'"il I '{({ q{sBs eA< EqE<q fi$ t

13.Whyisitthatonlysulphideores.rreconcentratedbyfrothfloatation
Processes?WhatistheroleofdepressantsinthefrothfloatationProcess
L+1.=2
of dressing of ores ?

cs-{ b"isd "thG<EF] c<F{a q:qT.Es
qfG$rq ftT sftYe- ct E{ ? cra Eqvil

qEGs qlc{s
"tReaeqs ffi w<l< Pfr-+t frl

32T CHEM t5l CLtrtkl.

74. Answer arry two I

fr. llrqr dr+Uw fr"r :

(a) Tia* compounds are colourless in aqueous solution but Ti3*
compounds are violet coloured. Explain. 2

qft{ Til* drair<r< <"ft{, frtr sfir ri,i drir-<t<< <<.f mgfta1 131",,
s-{ll

(b) What is meant by 'disproportionation' of an oxidation state ? Give an
example. 2

qf<"i qf,Et stl{ q{.fr?lfi"t St {r(4 frr eil tqf,5q fr$r

@ Actinoid contraction. is greater than lanthanoid contraction. I4rhy ?
2

- cd-cq{'{s c(IslD-{e$ q&Qs xmb-{ r<&r ftar

15. (0 Write the IUPAC name of the following compound : 1

ig-E< d',atrtt< IUPAC {n fr{t s

IPt(No2)(NH3)BrCl]

(iil How many geometrical isomers will be possible for
[Pi(Py)(NHr)BrCl] compound ? L

[Pr(Py)(NH3)BrCl] dElcift< qirkqT] c{rTtft ftai;fit cq-{ffi 4rc<r

32TCHEM t6l

oR / qctilt

Write the hybridization state of central atom of the following co-ordination
complexes along with their magnetic properties. 2

ffi ufi4 651 cott< 6<'ft "F{rt< x$<q q-{t qtsqrfto frfu< UxfrR
E"R fiTCT fr{I I

[Cu(NHr)rl2- and (q5; [N,(Co)1]

L6. What is the prime cause of depression ? Give an example of antidepressant
drug. 2

R<sron qq4 sFrq frz q&ftsdqstft Qs< qbn Eqr{<q fi$ r

oR /q4a7

What is the function of a Tranquilizer ? Give an example of a compound
which can be used both as Antiseptic and Disinfectants. 2

IqsR <l ffism< fr sll s6< ? .sil d'a< Efl<q fi{T, Flttl cfitRffw5<r<+
ffoqanre Kfls-qr< fum +c'<l

17. Mention the type of Semiconductor when Sl doped with P. A solid
, compound XY has NnCl structure. If the radius of the cahon (X*) is 100prz
then calculate the radius of the anion (Y-). 1+2=3

siE P u'A( +Rrq csF graF< qif{m aibq t< 4n fr?tl r eH ofta ffi't
XY{ NaCl{ ql',Cqr {fr .stFq (r)< <ilfl( 100pn Q{, cscs qqFH
'lbq
(Y)< <flcl{fifi ml

32T CHEM 17 I Anfi.

oR /q2l4l

What are semiconductors ? How electrical conductivity of semiconductors
vary with temperature ? Give one example of intrinsic semiconductors.
1+1+1=3

q(qffi ftr q(qffi<r<< fitrs qffiiEroR qqs c+tf$ qfuq qn?
qsrcRs q{"fffi<< eE Eqr<q fut

18. In the electrochemical cell ;
Zn / ZnSOq (}'llvt) // CttSOa (0'1M) / Ctt ,
the e.m.f. of the Deniel cell is Er. When the concentration of ZnSOa changed
to l'0M and CaSOa changed to 0'01M, the e.m.f. of the ce1l changes to E2.
Estabiish the relation between E1 and E2. 3

sEFkrs <Iclrfr$ cslrlBlE
Zn / ZnSOa (0'1.M) // CUSOa (0'1M) / Ctt ,

qqfi {<l q{, colqctF e.m.f. TFI E2 ?E iffifi s{ I !sG$ qi e , qrs E2 < Tlqs
q-q6 Rt'F cll

oR /q*t
The molar conductance of 0'1rrr aqueous solution of NH+OH is
9.54olrnt-7 otr2tllol-] and at infinite dilution molar conductance is
'238 ohrr-TcnPntol-1. Calculate ihe degree of ionization of ammouium

hydroxirle at the same concentration and temperature' 3

O.:rnt NHTOH qfil r<< rqF "im]-< TF 9'54olrrrlcnr2nrol-1qa wftl
qTsls {tsI< "iffisf< ffi q{ 238 o/rr rldtr2nnl-1| 'sr$ ttl.trst qs V{Gsls
q\Fffi qEgAmg< firilq{ {rqr< {q ti"l{l <EIt I

32T CHEM l8l

L9. (n) Define molality of a solution.

qA E{< rcdfrG< c<gtfiTtl

(b) State Henry's law. At the same temperature, COz gas is more soluble
in water than 02 gas. Which one of them will have higher value of
Ku?

FC{ {qdl fr{r ers EsqE "flfts co2 crfw &<ftl.q oz cetqds
qiist 6sF6l c{E< Ka <qF'c<&q<?

20. Decomposition of HzOz follows a first order reaction. In 50 minutes
the concentrati on of HzOz decreases from 0.5 to 0,125M in one such
decomposition. When the concentrati on of H2O2 reaches 0.05M, what is
the rate of formation of 02? 3

a2o2 < frq$<.t Rffit EeN @T< Ffrfl t H2o24 tft.EEI 50 frffis o.s < "r<t
0'125M ?E s6c r 6qG-$ H2O2< rlt.Esl 0.05M'tR, N&fl or< tsqnq{< s{ fuF
q<r

oR / qqqt

Show that the integrated rate for a first order reaction R -+ P is

,,-,-
K
2.303, tRt 3
'oeEi
ffi'{s$ c{ aqn @Tr frfuqr R-+P < <IF w{s4q {ft-fiqdl ?czs

K
2.3O3,^^ [R]o
,, =-LOO- "-" I

t [R]

32T CHEM tel Conttl.

2t. What happens, when - (any three) 1+1+1=3

fr srt, c{G$ - (fufrffiD

(a) PaOls is treated with dil. HNO3
E1 HNO3<Efls P4O1ofrfu-Tt S(<

(b) Cl2 is treated with hot and conc. NaOH
eit.r NnoH < E iE Cl2 frfuTl or<

k) Reaction of ammonia with excess Cl2 gas
qfi-+ qfutq< cl2 (tfF E ls ,fl'fiTn frfufl

(d) Orthophosporic acid is heated
qafoEsR$ sFs Esg ctE{

Write the chemical reactions for following transformations : (any tuto)
-1+1=2

firare q6<-6c<t< q-'r* +Rdo {crnfr-s ftfurq< frrtl s (firmjt"I fbD

O Benzene to Phenol

c<d&-d< "K ft{h

(i) Toluene to Benzvl alcohol

wi< "Kt KdsrR{ sETt{
(iil Benzene to Diphenyl
[<q&-d< "t<t uffi461

32T CHEM [10 ]

.4

(b) Why aryl halide undergoes eiectrophilic substitution reaction rather
than nucleophilic substitution reaction ? L

€{R{ RqRcs fu fr68qftfr+ sftql"F ftfu$ 6qp-{$R ?rEB'frFrs
e&qr"rq frfu{.t cr':p<mr

23. (n) Identify A and B. 2

A qK B-s Fqfs mtr

(b) Write only the chemical reactions of the following: (any one) 1.

ffiFts< <rc< cfiFT {m{R-{ R&lt fr<n ". (fu ,qbt)

(i) Carbylaminereaction
flffi{ frfurt
(ii) Hoffmann bromamide reaction

{Tcnr <TNW frfuTt

24. (n) Give an example of biodegradable polymer. 1

Q-<Rfi-qqmril r<atft qbt< Eqr<q finrr

32T CHEM [11] Contd.

I

@) Match the following correctly : 2

ffiflrcm$ sqts rirqt<I s

Polymer (TErqtft) Monomer (,ssfTlft)

n. Natural Rubber i 1,3 Butadiene (f, a ffiq) +

(ap&+ <-<<) Stvrene (ERT<1 )

b. Neoprene ii. 1,3 Butadiene (1, 3 ffiq) +

(fiq'A{) acrylonitrile (q@Ed'{EEF)

c. Buna-N ($t-N) iii. Chloroprene (P?itl)

d. Buna-S (gl-S) 'lzr. Isoprene (qHA{)

,25. (n) Write the chemical reactions for following transformations : (any tuto)
L+1.=2

firqre qR-or'qm< q-"F sRtE <tr{fr$ RfuTm< fu<n z 1ft6161VV1;

O Benzyl chloride to benzyl alcohol

rdsrRq 35'<Es< "r<l 65{qR-{ .s4s',Ei

(it Methyl magnesium bromitle to 2-methyl-propan-2-ol
fr{Ef, crt|cqfurn <'TEs< "K z-frqtEq-a''iFl-2-q'd
(iii) AcetoPhenone from Phenol
c<t{!-{ "KI effi'(Iq4

32TCHEM 112],

(b) Arrange the following in increasing order of acidity :

ffi ffiflr+Ers qksq< W:cao )nqmt s

A
OH
'i"
ry" V)
I o
CH,
Q NO,

26. (a) What type of bonding helps in stabilizing the secondary structure of
proteins ? 1,

fr {ffiRra g'F-+< cw-oetft ri'rd IR< +Rdq r{Tr $r<e

(b) Answer the following questions : (any tzto)

O How are vitamins classified ? Name the vitamin deficiency of
which causes scurvy. 2

eBfr-{$ mcdo ceff R-wra mt ql? ft ffiftl< qq-<< <rc< $lG
FFifr{ fi',rfi {lr, q"N ft{I r

(i0 \,1/hat is glycogen ? How is it different from starch ?
sk?u{ ftz Et6tio E mrf+ lqoz

32T CHEM [13 ] Contd.

(ili) Name the protein which is present in hair. What type of protein
is this ? 2

EtdE am a'trr Rr< itl fr,tt rE rsrdd cqft{ q'fr{?
27. (a) Draw the structure of any one of the following : 1

vss EARE frt"|lrIt.rDF ri5{ \xfrsGl 3

O Chlorous acid

s'<l6,sFs
(it Sg

@) Answer the following qirestions : (any two)
E fi$ d{r{K< U€< frRI z (fr@trit ?tt)
(n Are the bond lengths of a1l five P- Cl bonds in PCl5 molecule
equal? Justify your answer. .2

pcls dr'fttn 6flf& liuuf{ p- ct < <rqfr e{ r-dn wcq? FNFT
Ere-+< q"rcm lG frmr
(it Explain why HNO2 behaves both as oxidizing as well as reducing
agent.

HNo2 c{ fra ur++ w+ 6q6" qT?ret K-{F|C< <{ cq'{(]T, <itllT o<t I

(ili) Vr/hen HCI reacts with finely powdered iron, it forms ferrous
chloride, and not ferric chloride. Explain, why ? 2

frR e& qE<"F qtig HCl cl Rfufl sRrd' a-r,<epkRvrqEq'F qn,
mR-+ elEs +ql ftlr <r't?[t Gt r

32TCHEM [14]

28. Complete the following reactions: 1x5:5

ffiRE Rfu$r<K q-'l{wt g

Conc. KOH
o

(it Hg2-oH'soo ,
CHz-C: C-H

CO, HCI
(iil ------------)
CuCl

CHe- CH: CH - CH2COOC2HT+#4

o

(zt) *les1wH;, ].

-

x-
32T CHEM [15]

I

32T CHEM [16]. 47+