-----
CLASS XII
ST. KABIR SCHOOL
PREBQ_ARD -1 EXAMINATION (2023-24)
CHEMISTRY (043)
uO
oo0-7<;
:: .:.--z;c,
M.M 70 TIME 3Hrs
-------------------------------------------------------------------------------------
--
one mark each.
INSTRUCTIONS: There are five sections in all. . All questions are compulsory. Section A has 1-16 questions
2 case study
Section B has 5 questions two mark each. Section C has 7 questions three mark each. section o has
k 2°?JJ31-f?'0!-J
only.
table
log
Use
questions. Section E has 3 questions five mark each. Draw diagram where necessary.
L,(J
SECTION-A
/
2.
3.
:: ,:2. 363 J _Qs>1 1
Amo~gst Ni(CO}J, [Ni(CN~; _and [NiC~
( N1(CO4, andrNIC lt are·d1~magnet1c and [Ni(CN)i, is paramagnetic. ~O ~ 1
NIC~ and [N1(CNJ"are diamagnetic and [Ni(CO) J is paramagnetic
D
..
D
K
-.:
1--t0
etic_
N~(CO),,. and [N~(CN)i,are diamagnetic and [NICl:is paramagn
0(d) N1 CO) and [N1(CN) .are tetrahedral (p and (NICI is s uare planar
1
In the reac ion X- Product follows first order kinetics and in 40 minutes, the concentration
of~ changes from 0.,1 M to 0,025 M !hen rate o~actio n w~n concentration of 'X' is 0.01
3A7 x 10-M/min
(a) 1,73 x 10 M/min
M Is [log 4=0.6021]
d) 1.73 x 10-5 M/min
c 3A 7 x 1O°"'Mlmin
In the reaction 2NO + cI2~ 2NOCI, it has been found that doubling the concentratien of • 1
both the reactants increases the rate by a· factor of 8 but doubling the concentr ation of Cl,
alone, only doubles the rate. Which of the followin statemen t is correct?
b) The reaction is first order w.r.t. NO
· (a The reaction is second order w.r.t. Cl
e overall order of reaction is 3
he overall order of reaction is 2
o O 1.,1-, 1
Fe E-=0~4 V
standard E for half cell reactions are : Zn E~, 76 V
2
2
• 0 3.:JThe standard end of cell involving the reaction Fe + + Zn~-+-~ Zn + + Fe is
='1(.
4
<>4
V
0.32
d)
V
c +1.20
a) ..:Q.35 V (b +1.17 V
1
s
produce
ture
tempera
low
at
acid
nitrous
eous
aq
with
The compound which on reaction
0
0
an oily nitrosamine is
(c) (C2H5)2NH 1(d) C6H5NH 2
) CH3CH2NH2
(a) CH3NH2
1
1------,IL..-4 ------'~
Raoult's law at 35 degree ce ·us are
from
Mh<ture not showing positive deviation
aniline
+
henol
3
C6H5CH
+
C6H6
c
3
CH3COCH
+
CS2
a) CC\4 + Methanol b
ate=k[H2 [Br2]1 12 The molecularity and order for reaction 1
For the reaction: H2 + Br2 2HBr
\.
d 1and1/2 & 1and1/2 •
c and1/2 & 2
b 2 & 1and1/2
is: a 2 & 2
1
to
took
it
In 30 minutes, a first-order reaction 1s 50% complete. Calculate the amount of time
8.
J
complete 87.5 percent of the reactio
minutes
120
D
minutes
9
C
minu.tes
60
B
minutes
30
A)
1
Which one of the following characte • cs of the transition metals is associated with higher
r
b) Paramagnetic behaviou
catalytic activity? a) High enthalpy of atomization
a ~ariable oxidation states
c Colour of h drate ions
1
Ttie carboxylic acid that does not undergo HVZ reaction is
d CH3 iZCOOH
c (CH3CH2CH2COOH
b CH3 2COOH
a CH3COOH
2
1
in
cro42-(yellow) changes Cr2O1 1orange) in pH=X and vice versa pH=Y~the value of X and Y
D 7 and 7
c 8 and 5
b 6 and 5
a 6 and 8
ill be
1
system will be
d4
for
ion
configurat
electronic
t
corr
the
If b.o < p then
'
d t2 2 e 2
c t2 0 e 4
2 3e 1
A t2 4 e 0
of two statements, one is
consists
questions
following
the
of
Each
13-16):
Nos.
Directions (Q.
Assertion and the other is Reason. Give answer:
1
ssertion: Vanadium had the ability to exhibit a wide range of oxidation states.
13.
Reason: The standard potentials Vanadium are rather small, making a switch between oxidation
states relatively easy.
correct explanation of Assertion.
(a) Both A~sertion and Reason are true
nd Reason is the correct explana ,on o
e 10n nd Rea
(c) Assertion is fake but Reason is true. (d) Assertion is true but eason 15 wrong.
Assertion: DNA has a double strand helix structure.
Reason: The two strands in a DNA molecule are exactly similar
.
(a) Both Assertion and Reason are true but Reason is not
a correct explanation of Assertion.
(b) Both Assertion and Reason are true and Reason is the
correct explanation of Assertion.
(c) Assertion is fake but Reason is true. ®,sse rtion is true
but Reason is wrong.
15.
16.
1
18.
Assertion: Tertiary butylamine can be prepared by the action
of NH3 on tert-butylbromide.
Reason: Tertiary butyl bromide being 3° alkyl halide prefer
s to undergo elimination on the
treatment with a base.
(a) Both Assertion and Reason are true but Reason is not
a correct explanation of Asser tion.~
(b) Both Assertion and Reason are true an
eason is the correct explanation of Assertion.I
c Assertion is fake but Reason is true.,c d ssertion is true
but Reason is wron ..
ssertion: Aldehydes and ketones, both react with Tollens'
reagent to form silver mirror.
Reason: Both, aldehydes and ketones contain a carbonyl
group.
(a) Both Assertion and Reason are true but Reason is not
a correct explanation of Assertion.
b Both Assertion and Reason are true and Reason is the
correct explanation of Assertion.
c ssertion is fake but Reason is true.
d Assertion is true but Reason is wron
SECT ION-B
This sectio n conta ins 5 quest ions with internal choic e
in one quest ion. The following
25.
26.
1
2
~::s :::sc ::::n ~f:::: ::s: ::~: :~i: : : ~ : :,m:::
: : : : time will it take to reduce
the initial conce ntrati on of the reacta nt to1 /1 &th of its
initial value ?
Differ entiat e betwe en globu lar and fibrou s proteins.
./
24.
1
OR
2
tyame the linkag e that hold togeth er the amino acid molec
ules in a protein.
..
(\g(Na me the unit forme d by attach ment of nucleoside
to
phosp
horic
acid
at
5'
positio
n of
(
su ar moie
What wi\l be the produ ct forme d when· chlorobenzene reacts
with magnesium in presence 2
of d ether? Give e uation also.
State Henry 's law. Calcu late the solubility of CO in water
at 298 K under 760 mm Hg.
2
2
( KH for CO2 in water at 298 K is 1.25 x 106 mmH ).
•
Write the major product(s) in the following:
a) CH3CHCHCH2CN ----i) DIBA L-H- ------ --ii)H
3O+ ·--- ?
b CH3 CH2 OH ---C r03
,?
SECT ION-C
The formula [Co(NH3)5(CO3)]CI could represent a carbon
ate or a chloride. Write the structures
3
and names of ossible isomers. Comment on the stabilit
of this com lex
Explain how osmotic pressure is a colligative property? A
solution prepared by dissolving 10 g of a 3
protein in 100 cm 3 of aqueous solution has an osmotic pressu
re of 76mm Hg at 300 K Calculate
the m lar mass of the protein in kg mol- 1
a) !lowing reactions occur at cathode during electrolysis
of aqueous silver chloride solution
3
g+(aq) e- --+ Ag(s) Eo=+0.80V
H+(aq) + e- ---+ H2(g) Eo= 0..00V
On th asis of their standard reduction electrode potential
values, which reaction is feasible at
cat de and why?
( Define limiting molar conductivity. Why conductivity of
an electrolyte solution decreases with
the ecrease in concentration?
tate Faradays laws of electrolysis.
3
•
I ctrolysis of dilute aqueous NaCl solution was carried out
by passing 10 milliampere current.
time required to liberate 0.01 mol of H2 gas at the cathode
will be?
The rate constant of a first order reaction increases from 2
2
2
3
x 10- to f x 10- when the
temperature changes from 300 K to 310 K. Calculate the energ
y of activation (Ea).
g 2 = 0.301, log 3 = 0.4771, log 4 =0.6021)
Derive the inte rated ex ression for rate constant of first order
reaction.
a) Explain Lanthanoid contraction, its cause & consequenc
3
e?
.
.
b Write difference between actinoids and lanthanoids on the
basis of chemical activit • 2 ornts
Using Valence bond theory, explain the following in relation
3
to the paramagnetic complex
/ex - inn er ,
nt value c) type of co mp
me
mo
c
eti
gn
ma
b)
on
3
a) type of hybridizati
[Mn(CN)s] uter orbital com lex
SE CT IO N- D
on s giving rise to th e
ir atoms receive ele ctr
the
in
e/
/ev
y
erg
en
Cd an d Hg ar e no t
nultimate
series. However, Zn,
The d-orbitals of the pe
d
d5
an
4d
,
3d
.,
i.e
s
ter ist ic propE:rties !i~e
ition metal
exhibit certain ch ar ac
three rows of the trans
nts
ty
me
ele
ion
sit
an
Tr
alloys, ca tal yti c act1v1
elements.
tion of coloured ions,
regarded as transition
ma
for
n,
tio
ma
for
int
lex
ltin g po
s, comp
•
) and ha ve a hig-h~me
variable oxidation stab/e
I
pt Zn, Cd and Hg
·--ce
(ex
rd
·--ha
•
are
s
·
i
tal
·
me
_
_
.._
.
n
.
~_
__
~
_j_
etc. Transition
Cu
[ Ni
~---.------
l:1tmcnt
----
/ r' tOm ~llU ll ~111l~lpy
<>JI
f11"1 1onew.1w11 ~mhalpy
1245
• I py
na
•
•
I JI 1•·1 1om
-.11•1"n cnr
1
.. _\' __J
Ti
Sc
•
Lt~o
I
2451 1' 2721
1.6 .n·
IJ.J :Y
J . .:'ln
{152
(,.,o
656
Cr
I
J
J.P o
1~35
2~7-4
2995
-:-17
/
1·c ~- _ • _ Co
r6 2
I
UA J \'
I·
l..5 7V
-·---..l.---~ ----~-
7..;~
Jo.{~
l 75 7
196.::
o.2 sv '
v / o.. i4v
, J.'\V: o.? 1\· J-1 .~s
0.2 6\' /
n6
')O~ kl ml
I i36
~- 9-3_M_J--.,,-_:6_J__ __-~·'
_/l_ _. ~·
I 2'){~ _323
1513 r !56-t
' .~25~
7 5~
o.2 ;v
'
,r,__;.! V'
.),
o.7 6V
I 10. 77\ ' • l.9 7\'
L __ __ __ _ -- · ··--·-
ns
er the following questio
?
ta l an d no t in me ta l -.
e hydrogen from acids
y does co pp e~ t rep/ac is exhibited in oxo-anions of a tra ns itio n me
n tha t of Zn ?
highest ox id ion state
~
thalpy of Cr is low er tha ?
en
n
tio
isa
ion
t
firs
hy
.W
4
es.
ve than ex ec ted
,
and Zn are more ne ati lution co nta ini ng on e mo le of ele ctr oly te
h E values for Mn, Ni
so
so
,
of
ea
ce
lut ion is the conductan
ge cr os s- se cti on al ar
Molar co nd uc tiv ity of so es ha vin g un it length between the m an d lar nd uc ta nc e of th e
ctr od
co nd uc tiv ity is the co
ke pt be tw ee n tw o ele
e ar e m an y
In oth er words, mo lar
te.
oly
ctr
ele
tiv ity ce ll at un it. Th er
the
uc
in
nd
n
co
a
of
as to co nta
es
od
ctr
n, mo bil ity , sa lva tio
pt between the ele
er atu re , co nc en tra tio
mp
Te
s.
electrolytic so lut ion ke
ce
tan
bs
su
of
co nd uc tiv ity
factors 1ch aff ec t the
lcu la te its
.1 S cm 2 mo l-1 . Ca
46
m.
is
id
ac
ic
no
tha
etc. ar few of the
of 0.025 mo / L-1 me
:6 S cm 2 mo l-1
The molar conductivity
t Gi ve n A (H +) =3 49
tan
ns
co
n
tio
cia
so
dis
d
egree of dissociation an cm 2 mo l-1
of
S
.6
54
=
)
Ogr ea te r co nd uc tio n M
CO
(H
A
nd
wh ich pa ir wi ll all ow
1..
n
or
so
rea
ion
th
lut
wi
so
t
H
dic
OO
pre
f the fol low ing pairs,
60 °C . (ii) 0. 1 M CH 3C
3D°C or sil ve r wi re at I sol •
c.
at
re
wi
r
ve
§il
(i)
ty:
• e
at 20 °C or
ion
lut
so
I
KC
iii
.
ion
CH3COOH s
SE CT IO N- E
ld 2 mo le of Ag CI .
excess of Ag NO 3 to yie
h
wit
cts
rea
2O
6H
.
3
o.
a ne mole of CrCl
. Write IUPAC name als
Write formula of complex
:
b) Explain the following
ounds.
ceptionally stable comp
ex
are
ls
ny
mplexes.
i)Metal carbo
co
ral
ed
not form low spin octah
dil ute so lut ion s
11 Nickel (II) does
of different colours in
are
2+
5
)sJ
2O
(H
[Fe
d
an
111) e CN)sJ4s in
conductivity.
ga
d
n
an
go
ty
ar
ivi
of
ist
y
res
ilit
m
lub
ter
so
lain the
~ of 6 bar. Ca lcu lat e the
exerts a partial pressun solved in water, KH = 40 kb ar )
?n
arg
t
tha
e
u~
(b
,
tant for argon dis
(Given Henry s law cons t (Kb)
w
constan
in wa te r ha s th e
~ n e Mo/al elevation
) pe r litr e of s<;>lution
l-1
mo
g
60
=
ss
~a
r
mol-1) in w t
ng _15 g ~rea (mola
(m ola r ma ss = 18 0 g
se
co
a er.
glu
( ~ ~01utio~ containi
of
ion
lut
so
a
(1sotornc) as
s me 0osmotic pressure lucose resent in one litre of its solution.
ne
ob tai d:
5
fol low ing re su lts we re
Calculate the mass of
the
,
ion
lut
so
s
ou
ue
aq
in
te
eta
ac
l
thy
For the hydrolysis of me
60
30
O
0
0
0
I
0
32
33
4
t/s
L-1
(CH3COOCH3] / mo l
0.60 0.30 0.1 S
·- •
t ·
c
the
as
on
cti
rea
ins co ns tan t.
er
ma
ord
re
eudo first
e
tim
So w that it follows ps
the
e of reaction betwee~
be aff ec :ee ;:~ ds •
lcu_late the average r~t
(
on for a giv en reaction
cti
rea
of
e~ d
e
rat
the
ll
wi
wa s tak·in
Iac e 1s ec re as ed
)I xplam ho ~ and why
e at which the reaction
tur
era
n·
ter
the
II.
• a catal st 1s added.
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