final jee–main examination – april,2019
TRANSCRIPT
1
ALLEN
Final JEE -Main Exam April,2019/08-04-2019/Evening Session
1. Calculate the standard cell potential in(V) of thecell in which following reaction takes place :Fe2+(aq) + Ag+(aq) ® Fe3+(aq) + Ag(s)Given that
oAg / Ag
E xV+ =
2oFe / Fe
E yV+ =
3oFe / Fe
E zV+ =
(1) x + 2y – 3z (2) x – z(3) x – y (4) x + y – zOfficial Ans. by NTA (1)
Sol. Fe+2(aq) + Ag+(aq) ® Fe+3(aq) + Ag(s)Cell reactionanode : Fe+2(aq) ® Fe+3(aq) + e1 ;
2 3oFe /Fe
E mV+ + =
cathode : Ag+ (aq) + e1 ® Ag(s) ;
oAg /Ag
E xV+ =
Þ cell standard potential = (m + x)V\ to find 'm';Fe+2 + 2e1® Fe ;
o o1 1E yV G – (2Fy)= Þ D =
Fe+3 + 3e1® Fe ;
o o2 2E zV G – (3Fz)= Þ D =
Fe+2(aq) ® Fe+3(aq) + e1;
o o3 3E mV G – (1Fm)= Þ D =
o o o3 1 2G G – GD = D D = (–2Fy + 3Fz) = –Fm
Þ m = (2y – 3z)
Þ ocellE = (x + 2y – 3z)V
FINAL JEE–MAIN EXAMINATION – APRIL,2019(Held On Monday 08th APRIL, 2019) TIME : 2 : 30 PM To 5 : 30 PM
CHEMISTRY TEST PAPER WITH ANSWER & SOLUTION
2. The major product in the following reaction is :
NH2
N
NNH
N + Base
3CH I ¾¾¾®
(1)
NH2
NCH3
NNH
N +
(2)
NH2
N
NNCH3
N
(3)
NH2
N
NNH
N
CH3
+(4)
NHCH3
N
NNH
N
Official Ans. by NTA (2)ALLEN Ans. (Bonus)
Sol. because one double bond is missing in all givenoption. So aromaticity is lost in both the ring.
3. For the following reactions, equilibriumconstants are given :S(s) + O2(g) � SO2(g); K1 = 1052
2S(s) + 3O2(g) � 2SO3(g); K2 = 10129
The equilibrium constant for the reaction,2SO2(g) + O2(g) � 2SO3(g) is :(1) 10181 (2) 10154 (3) 1025 (4) 1077
Official Ans. by NTA (3)Sol. S(s) + O2(g) � SO2(g) K1 = 1052 ...(1)
2S(s) + 3O2(g)�2SO3(g) K2 = 10129 ...(2)2SO2(g) + O2(g)�2SO3(g) K3 = xmultiplying equation (1) by 2;
2SO(s) + 2O2(g)�2SO2(g) 1041K 10¢ = ...(3)
Þ Substracting (3) from (2); we get
2 2 32SO (g) O (g) 2SO (g)+ ������ ;
Keq = 10(129 – 104) = 1025
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ALLEN
Final JEE -Main Exam April,2019/08-04-2019/Evening Session
4. The ion that has sp3d2 hybridization for thecentral atom, is :
(1) –2[ICI ] (2) –
6[IF ]
(3) –4[ICI ] (4) –
2[BrF ]Official Ans. by NTA (3)
Sol. Chemical species Hybridisation ofcentral atom
–2ICl sp3d
–6IF sp3d3
–4ICl sp3d2
–2BrF sp3d
5. The structure of Nylon-6 is :
(1) (CH ) – C – N2 6
O H
n
(2) (CH ) – C – N2 4
O H
n
(3) C – (CH ) – N2 5
O H
n
(4) C – (CH ) – N2 6
O H
nOfficial Ans. by NTA (3)
Sol. C – (CH ) – N2 5
O H
n
Nylon-6
6. The major product of the following reaction is:
O
Cl t
2 4
(1) BuOK(2) Conc. H SO / D¾¾¾¾¾¾¾®
(1)
O
(2) O
(3)
O
(4) O
Official Ans. by NTA (4)
Sol.
O
Clt–BuOK
E2
O
H / D+
O – H+
O
OH+
H
TautomerOH
7. The major product of the following reaction is:
CH3
Cl
2
2
(1) Cl / h(2) H O,
nD
¾¾¾¾®
(1)
CH2OH
Cl
(2)
CHCl2
Cl
(3)
CO2H
Cl
(4)
CHO
Cl
Official Ans. by NTA (4)
Sol.
CH3
Cl
CHCl2
Cl
CHO
Cl
Cl / 2 D H O2D
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ALLEN
Final JEE -Main Exam April,2019/08-04-2019/Evening Session
8. The percentage composition of carbon by molein methane is :(1) 80% (2) 25% (3) 75% (4) 20%Official Ans. by NTA (4)
Sol. CH4
% by mole of carbon = 1molatom
1005molatom
´
= 20%9. The IUPAC symbol for the element with atomic
number 119 would be :(1) unh (2) uun (3) une (4) uueOfficial Ans. by NTA (4)
Sol. Symbol Atomic numberunh 106uun 110une 109uue 119
10. The compound that inhibits the growth oftumors is :(1) cis-[Pd(Cl)2(NH3)2](2) cis-[Pt(Cl)2(NH3)2](3) trans-[Pt(Cl)2(NH3)2](4) trans-[Pd(Cl)2(NH3)2]Official Ans. by NTA (2)
Sol. cis–[PtCl2(NH3)2] is used in chemotherapy toinhibits the growth of tumors.
11. The covalent alkaline earth metal halide(X = Cl, Br, I) is :(1) CaX2 (2) SrX2 (3) BeX2 (4) MgX2
Official Ans. by NTA (3)Sol. All halides of Be are predominantly covalent
in nature.12. The major product obtained in the following
reaction is :
CN O
NH2
3
2
(i)CHCl / KOH(ii)Pd / C/H
¾¾¾¾¾¾®
(1)
H N2 OH
NCH3
H
(2)
CN O
NCH3
H
(3)
CN OH
NCH3
H
(4)
CN OH
NCHCl2
H
Official Ans. by NTA (1)Sol.
NH2
NH2
OH
H
CN O
NC
OCN
CHCl / KOH3
Pd/C/H2
NCH3
Carbylaminereaction
13. The statement that is INCORRECT about theinterstitial compounds is :(1) They have high melting points(2) They are chemically reactive(3) They have metallic conductivity(4) They are very hardOfficial Ans. by NTA (2)
Sol. Generally interstitial compounds are chemicalyinert.
14. The maximum prescribed concentration ofcopper in drinking water is:(1) 5 ppm (2) 0.5 ppm(3) 0.05 ppm (4) 3 ppmOfficial Ans. by NTA (4)
Sol. The maximum prescribed concentration of Cuin drinking water is 3 ppm.
15. The calculated spin-only magnetic moments(BM) of the anionic and cationic species of[Fe(H2O)6]2 and [Fe(CN)6], respectively, are :(1) 4.9 and 0 (2) 2.84 and 5.92(3) 0 and 4.9 (4) 0 and 5.92Official Ans. by NTA (3)
Sol. Complex is [Fe (H2O)6]2 [Fe(CN)6]
Complex ion
Configuration No. of unpaired electrons
Magnetic moment
[Fe(H2O)6]2+ t2g
4 eg2 4 4.9 BM
[Fe(CN)6]4– t2g6eg
0 0 0
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Final JEE -Main Exam April,2019/08-04-2019/Evening Session
16. 0.27 g of a long chain fatty acid was dissolved
in 100 cm3 of hexane. 10 mL of this solution
was added dropwise to the surface of water in
a round watch glass. Hexane evaporates and a
monolayer is formed. The distance from edge
to centre of the watch glass is 10 cm. What is
the height of the monolayer?
[Density of fatty acid = 0.9 g cm–3, p = 3]
(1) 10–8 m (2) 10–6 m
(3) 10–4 m (4) 10–2 m
Official Ans. by NTA (2)Sol. Radius of watchglass= 10 cm
Þ surface area = pr2 = 3 × (10 cm)2
= 300 cm2
mass of fatty acid in 10 ml solution
=10 0.27
0.027gm100´
=
volume of fatty acid = 0.027g
0.9g / ml = 0.03 cm3
Þ Height = volume of fatty acid
surface area of watch glass
= 3
–62
0.03 cm0.0001 cm 10 m
300 cm= =
17. Among the following molecules / ions,
2– 2– 2–2 2 2 2C ,N ,O ,O
which one is diamagnetic and has the shortestbond length?
(1) 2–2C (2) 2–
2N (3) O2 (4) 2–2O
Official Ans. by NTA (1)
Sol.Chemical Species
Bond Order
Magnetic behaviour
C22–
3 diamagnetic N2
2– 2 paramagnetic O2 2 paramagnetic
O22– 1 diamagnetic
B.O. 1
bond lengthµ
18. 5 moles of an ideal gas at 100 K are allowed
to undergo reversible compression till its
temperature becomes 200 K.
If CV = 28 JK–1mol–1, calculate DU and DpV for
this process. (R = 8.0 JK–1 mol–1]
(1) DU = 14 kJ; D(pV) = 4 kJ
(2) DU = 14 kJ; D(pV) = 18 kJ
(3) DU = 2.8 kJ; D(pV) = 0.8 kJ
(4) DU = 14 kJ; D(pV) = 0.8 kJ
Official Ans. by NTA (1)
Sol. n = 5; Ti = 100 K; Tf = 200 K;
CV = 28 J/mol K; Ideal gas
DU = nCVDT
= 5 mol × 28 J/mol K × (200 – 100) K
= 14,000 J = 14 kJ
Þ Cp = Cv + R = (28 + 8) J/mol K
= 36 J/mol K
Þ DH = nCpDT = 5 mol × 36 J/mol K × 100 K
= 18000 J = 18 kJ
DH = DU + D(PV)
Þ D(PV) = DH – DU = (18 – 14) kJ = 4 kJ
19. Which one of the following alkenes when
treated with HCl yields majorly an anti
Markovnikov product?
(1) F3C – CH = CH2
(2) Cl – CH = CH2
(3) CH3O – CH = CH2
(4) H2N – CH = CH2
Official Ans. by NTA (1)
Sol. CF3–CH=CH2HCl¾¾¾® CF – CH – CH3 2
H
CF – CH – CH3 2
H Cl
Due to higher e– withdrawing nature of CF3
group.It follow anti markovnikoff product
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ALLEN
Final JEE -Main Exam April,2019/08-04-2019/Evening Session
20. For a reaction scheme 1 2k kA B C¾¾® ¾¾® , if
the rate of formation of B is set to be zero thenthe concentration of B is given by :
(1)1
2
k[A]
k
æ öç ÷è ø
(2) (k1 + k2) [A]
(3) k1k2[A] (4) (k1 – k2) [A]Official Ans. by NTA (1)
Sol. 1 2K KA B C¾¾® ¾¾®
1 2d[B]
0 K [A] K [B]dt
= = -
Þ [B] = 1
2
K[A]
K
21. Which of the following compounds will showthe maximum enol content?(1) CH3COCH2COCH3
(2) CH3COCH3
(3) CH3COCH2CONH2
(4) CH3COCH2COOC2H5
Official Ans. by NTA (1)Sol. Solution
O
CH – C – CH3 2 – C – CH3
O
KetoCH – C3
OH
O
C – CH3CHEnol
Due to intramolecular H-bonding andresonance stabilisation enol content ismaximum
22. The correct statement about ICl5 and –4ICl is
(1) ICl5 is trigonal bipyramidal and –4ICl is
tetrahedral.
(2) ICl5 is square pyramidal and –4ICl is
tetrahedral.
(3) ICl5 is square pyramidal and –4ICl is square
planar.(4) Both are isostructural.Official Ans. by NTA (3)
Sol.
Chemical species
Hybridisation Shape
ICl5 sp3d2 Square pyramidal
ICl4– sp3d2 Square planar
I
ClCl
Cl Cl
Cl
I
ClCl
Cl Cl
–ICl4
–ICl 5
23. The major product obtained in the followingreaction is
CH3
OHC
O NaOH
D¾¾¾®
(1)
O
CH3
(2) O CH3
HH3C
(3) O CH2
HH3C
(4)
O
CH3
Official Ans. by NTA (4)Sol.
CH3
OHC
O
O
CH3
NaOHD
Intramolecularaldol condensation
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Final JEE -Main Exam April,2019/08-04-2019/Evening Session
24. Fructose and glucose can be distinguished by :
(1) Fehling's test
(2) Barfoed's test
(3) Benedict's test
(4) Seliwanoff's test
Official Ans. by NTA (4)
Sol. Seliwanoff's test is used to distinguished aldoseand ketose group.
25. If p is the momentum of the fastest electronejected from a metal surface after the irradiationof light having wavelength l, then for 1.5 pmomentum of the photoelectron, thewavelength of the light should be:
(Assume kinetic energy of ejectedphotoelectron to be very high in comparisonto work function)
(1)12
l (2) 34
l
(3) 23
l (4) 49
l
Official Ans. by NTA (4)
Sol. h KEn -f=
incident
hcKEæ öÞ = +fç ÷lè ø
incident
hcKEæ ö
ç ÷lè ø;
KE = 2
incident
p hc hc2m
= =l l ...(1)
Þ2 2p (1.5) hc
2m´
=¢l
...(2)
divide (1) and (2)
(1.5)2 = l¢l
49l¢Þl =
26. Consider the bcc unit cells of the solids 1 and2 with the position of atoms as shown below.The radius of atom B is twice that of atom A.The unit cell edge length is 50% more in solid2 than in 1. What is the approximate packingefficiency in solid 2?
A
A
A A
A
A
A
AA
Solid 1
A
A
A A
A
A
A
A
B
Solid 2
(1) 45% (2) 65% (3) 90% (4) 75%Official Ans. by NTA (3)
Sol. p.f. =
3 3eff A eff B
A B3
4 4z r z r
3 3
a
æ ö æ ö´ p + ´ pç ÷ ç ÷è ø è ø
2(rA + rB) = 3a
Þ 2(rA + 2rA) = 3a
ÞA2 3 r a=
Þ p.f.=( )3 3
A A
3A
4 4 41 r 8r 9
3 3 38 3 3 r 8 3 3 2 3
´ p + p ´ p p= =
´ ´
p. efficiency = 100 90%2 3
p´ ;
27. Polysubstitution is a major drawback in:(1) Reimer Tiemann reaction(2) Friedel Craft's acylation(3) Friedel Craft's alkylation(4) Acetylation of anilineOfficial Ans. by NTA (3)
Sol. In Friedal crafts alkylation product obtainedis more activated and hence polysubtitutionwill take place.
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Final JEE -Main Exam April,2019/08-04-2019/Evening Session
28. The Mond process is used for the
(1) extraction of Mo
(2) Purification of Ni
(3) Purification of Zr and Ti
(4) Extraction of Zn
Official Ans. by NTA (2)
Sol. Mond's process is used for the purification ofNickel.
29. The strength of 11.2 volume solution of H2O2
is : [Given that molar mass of H = 1 g mol–1
and O = 16 g mol–1]
(1) 13.6% (2) 3.4%
(3) 34% (4) 1.7%
Official Ans. by NTA (2)
Sol. Volume strength = 11.2 × molarity = 11.2
Þ molarity = 1 M
Þ strength = 34 g/L
Þ % w/w = 34
100 3.4%1000
´ =
30. For the solution of the gases w, x, y and z inwater at 298K, the Henrys law constants (KH)are 0.5, 2, 35 and 40 kbar, respectively. Thecorrect plot for the given data is :-
(1)
(0,0) mole fractionof water
x w
yz
partialpressure
(2)
(0,0) mole fractionof water
z
partialpressure
x
w
y
(3)
(0,0) mole fractionof water
z
partialpressure
x w
y
(4)
(0,0) mole fractionof water
partialpressure
z
y
x
w
Official Ans. by NTA (3)
Sol.2
gasH
H O gas
np k
n n
æ ö= ´ç ÷ç ÷+è ø
2
2
H OH
H O gas
nk 1 –
n n
æ ö= ç ÷ç ÷+è ø
Þ p = kH – kH × 2H Oc
p = (–kH) × 2H Oc + kH
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