1. No category

JEE MAIN 2015
CHEMISTRY
QUESTION PAPER & SOLUTION
61. The vapour pressure of acetone at 20o C is 185 torr. When 1.2 g of a non-volatile substance was
dissolved in 100g of acetone at 20o C, its vapour pressure was 183 torr. The molar mass
(g mol1 ) of the substance is
(A) 488
(B) 32
Solution: (C)
(C) 64
(D) 128
Po (acetone)  185 torr
Now,
P o (acetone)  P(acetone)
P o (acetone)
1.2
185  183
M


1.2 100
185

M
58
(M  64)
 Xsolute
62. 3 g of activated charcoal was added to 50 mL of acetic acid solution (0.06N) in a flask. After an
hour its was filtered and the strength of the filtrate was found to be 0.042 N. The amount of
acetic acid absorbed (per gram of charcoal) is:
(A) 54 mg
(B) 18 mg
(C) 36 mg
(D) 42 mg
Solution: (B)
Millieq. Of Acetic acid before absorption  0.06N  50
 3 meq
Millieq of acetic acid after absorption  0.042  50
 2.1 meq
Thus, millieq of CH3COOH absorbed  (3  2.1) meq  0.9 meq
10
Thus mass of CH3COOH absorbed by 3g charcoal  0.9 
mg
1
0.9  60
 mass of CH3COOH absorbed/gram of charcoal 
approximate analysis.
3
63. Which of the following is the energy of a possible excited state of hydrogen?
(A) 6.8 eV
(B) 13.6 eV
(C) 6.8 eV
(D) 3.4 eV
Solution (D)
Energy of electron is 2nd orbit of H  atom  3.4 eV
64. Which among the following is the most reactive?
(A) ICl
(B) Cl2
(C) Br2
(D) I2
Solution: (A)
Since, qut of all the given molecules i.e. ICl, Cl2,Br2, only ICl is polar, thus most reactive


I  Cl
65. Which polymer is used in the manufacture of paints and lacquers?
(A) Poly vinyl chloride (B) Bakelite
(C) Glyptal
Solution : (A)
PVC is used in paints
(D) Polypropene
1
66. The molecular formula of a commercial resin used for exchanging ions in water softening is
C8H7SO3Na (Mol. wt. 206) . What would be the maximum uptake of Ca 2 ions by the resin
when expressed in mole per gram resin?
1
1
1
2
(A)
(B)
(C)
(D)
412
103
206
309
Solution: (A)
The compound formed nuclear C8H7SO3Na is reacted with Ca 2 ion is (C8H7SO3 )2 Ca
i.e., 2 mole of resi. Reacts with 1 mole of Ca 2 ion
i.e., 2  206g combines with 1 mole of Ca 2 ion
1
i.e., 1g of resi. combines with 
moles of Ca 2
412
67. In Carius method of estimation of halogens, 250 mg of an organic compound gave 141 mg of
AgBr. The percentage of bromine in the compound is
(at.mass Ag  108; Br  80)
(A) 60
(B) 24
(C) 36
(D) 48
Solution: (B)
80 141
80
weight of AgBr

 100  24%
% of Br 

 100 
188 250
188 weight of organic compound
68. Assertion: Nitrogen and Oxygen are the main components in the atmosphere but these do not
react to form oxides of nitrogen.
Reason: The reaction between nitrogen and oxygen requires high temperature.
(A) Both the assertion and reason are incorrect
(B) Both assertion and reason are correct, and the reason is the correct explanation for the
assertion
(C) Both assertion and reason are correct, but the reason is not the correct explanation for the
assertion
(D) The assertion is incorrect, but the reason is correct
Solution: (B)
Both statement are correct & IInd state also explain the reason of first statement

N2  O2 
 NO
(highly endothermic process)
At low temperature N2 & O2 cannot React to each other. But at high temperature N2 & O2 can
reacts.
69. The following reaction is performed at 298K.
2NO(g)  O2(g)  2NO2(g)
The standard free energy of formation of NO(g) is 86.6 kJ/mol at 298K. What is the standard
free energy of formation of NO2(g) at 298K ? (Kp  1.6 1012 )
(A) 0.5[2  86,600  R(298) ln(1.6 1012 )]
(B) R(298) ln(1.6 1012 )  86600
(C) 86600  R(298) ln(1.6 1012 )
(D) 86600 
Solution: (A)
For the given reaction

2NO(g)  O2(g) 
 2NO2(g)
Goreaction  R(298) ln(1.6 1012 )
2
ln(1.6  1012 )
R(298)
Now, from herses low of constant heat summation
Goreaction   Goproducts  Goreac tants

  R(298) ln(1.6  1012 )  2  GoNO2  2  GoNO  1  GoO
2

  R(298) ln(1.6 1012 )  2  GoNO  2  86600  0
2


1
2  86600  R(298) ln(1.6  1012 )
2
70. Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater
than its lattice enthalpy?
(A) SrSO4
(B) CaSO4
(C) BeSO4
(D) BaSO4
Solution: (C)
For BeSO4 , hydration enthalpy is greater than lattice enthalpy, i.e. it is soluble salt.
 GoNO 
2
71. The number of geometric isomers that can exist for square planar [Pt(Cl)(py)(NH3 )(NH2OH) is
(py  pyridine) :
(A) 6
(B) 2
(C) 3
(D) 4
Solution: (C)

No. of geometrical isomers of Pt(Cl)(Py)(NH3 )(NH2OH)
Py
NH3
NH3
Cl
Cl
Pt
HONH2
Pt
Pt
Py
Py
NH3
NH2OH
Cl
NH2OH
Possible isomers are =3
72. The synthesis of alkyl fluorides is best accomplished by:
(A) Swarts reaction
(B) Free radical fluorination
(C) Sandmeyer’s reaction
(D) Finkelstein reaction
Solution: (A)
R  X  AgF  R  F  Ag x 
(ppt)
Swarts reaction)
73. The intermolecular interaction that is dependent on the inverse cube of distance between the
molecules is:
(A) hydrogen bond
(B) ion – ion interaction
(C) ion – dipole interaction
(D) London force
Solution: (A) According to our point of view Hydrogen bond is special case of dipole-dipole
interaction where molecule do not rotate thus,
1
Energy 
r3
74. In the context of the Hall-Heroult process for the extraction of Al, which of the following
statements is false?
(A) Na 3 AlF6 serves as the electrolyte
(B) CO and CO2 are produced in this process
(C) Al2O3 is mixed with CaF2 which lowers the melting point of the mixture and brings
conductivity
3
(D) Al3  is reduced at the cathode to form Al
Solution: (A)
In case of electrolysis of Al2O3 , Cryolite is added to solution to decreases the M.P. but Na3AlF6
is not considered as electrolyte.
75. Which of the following compound will exhibit geometrical isomerism?
(A) 1, 1-Diphenyl-1-propane
(B) 1-Phenyl – 2 – butane
(C) 3-Phenyl-1-butene
(D) 2-Phenyl -1-butene
Solution: (B)
Structure of 1-phenyl-2-butene
H
Ph
H
Thus, it will exhibit GI.
76. The ionic radii (in Å) of N3 ,O2 and F  are respectively:
(A) 1.71, 1.36 and 1.40
(B) 1.36, 1.40 and 1.71
(C) 1.36, 1.71 and 1.40
(D) 1.71, 1.40 and 1.36
Solution: (D)
Ionic size of N3  O2  F 
77. From the following statements regarding H2O2, choose the incorrect statement:
(A) It has to be kept away from dust
(B) It can act only as an oxidizing agent
(C) It decomposes on exposure to light
(D) It has to be stored in plastic or wax lined glass bottles in dark
Solution: (B)
H2O2 can act both as (oxidizing agent) as well as Reducing agent
78. Higher order (>3) reactions are rare due to
(A) loss of active species on collision
(B) low probability of simultaneous collision of all the reacting species
(C) increase in entropy and activation energy as more molecules are involved
(D) shifting of equilibrium towards reactants due to elastic collisions
Solution: (B)
Higher order reactions are how because of low probability of collision of all the reacting species,
simultaneously.
79. Match the catalyst to the correct processes:
Catalyst
Process
(A) TiCl3
(i) Wacker process
(B) PdCl2
(ii) Ziegler – Natta polymerization
(C) CuCl2
(iii) Contact process
(D) V2O5
(iv) Deacon’s process
(A) (A)-(iii), (B)-(i), (C)-(ii), (D)-(iv)
(B) (A)-(iii), (B)-(ii), (C)-(iv), (D)-(i)
(C) (A)-(ii), (B)-(i), (C)-(iv), (D)-(iii)
(D) (A)-(ii), (B)-(iii), (C)-(iv), (D)-(i)
Solution: (C)
Defined catalyst in Different process.
80. Which one has the highest boiling point?
(A) Xe
(B) He
4
(C) Ne
(D) Kr
Solution: (A)
Boiling Point  Molar mass
i.e. Xe has highest B.P.
81. In the reaction
NH2
NaNO /HCl
CuCN/KCN
Δ
2

 D 
 E + N2
o
0-5 C
CH3
the product E is
COOH
CH3
(A)
(B)
CH3
CN
CH3
H3C
(C)
(D)
Solution: (D)
NH2

N
2 Cl
NaNO /HCl
+ N2 


0-5 C
CH3
CH3
CN
CuCN/KCN
Δ
2


o
CH3
CH3
(E)
(D)
82. Which of the following compounds is not coloured yellow?
(A) BaCrO4
(B) Zn2[Fe(CN)6 ]
(C) K3[Co(NO2 )6 ]
Solution: (B)
(D) (NH4 )3[As(Mo3O10 )4 ]
83. Sodium metal crystallizes in a body centred cubic lattice with a unit cell edge of 4.29Å. The
radius of sodium atom is approximately:
(A) 0.93Å
(B) 1.86 Å
(C) 3.22 Å
(D) 5.72 Å
Solution: (B)
For BCC 4r  3a
 4rNa  3  4.29
rNa 
3  4.29
Å=1.86Å
4
5
84. The standard Gibbs energy change at 300 K for the reaction 2A  B  C is 2494.2J. At given
1
1
time, the composition of the reaction mixture is [A]  ,[B]  2 and [C]  . The reaction
2
2
proceeds in the: R  8.314J/K mol, e  2.718]
(A) reverse direction because Q  Kc
(B) Forward direction because Q  Kc
(C) Reverse direction because Q  Kc
(D) forward direction because Q  Kc
Solution: (C)

2A 
Go  2494.2J
B  C
1
1
Given [A]  , [B]  2, [C] 
2
2
1
2
[B] [C]
2 4
Qc 

2
2
[A]
1
 
2
Go  RT ln Kc
2494.2  8.314  300  ln Kc
2494.2
 ln Kc 
 1
8.314  300
1
1
Kc  e1  
e 2.718
 Qc  KC so reaction proceeds in backward direction.
85. Which compound would give 5-keto-2-methyl hexanal upon ozonolysis?
CH3
CH3
CH3
CH3
CH3
H3C
(A)
(B)
Solution: (C)
CH3
O3/Zn-H2O


CH3
(C)
(D)
CH3
O
CH3 - C - CH2 - CH2 - CH- CHO
CH3
CH3
5-keto-2-methyl hexanal
86. Which of the following compound is not an antacid?
(A) Ranitidine
(B) Aluminium hydroxide (C) Cimetidine
Solution: (D)
Phenelzine is anti-depressant.
KMnO
(D) Phenelzine
SOCl
H /Pd
BaSO4
2
2
4  A 
B 
 C,
87. In the following sequence of reactions Toluene 
product C is:
(A) C2H5CHO
6
(B) C6H5COOH
(C) C6H5CH3
(D) C6H5CH2OH
the
Solution: (A)
O
CH3
KMnO
4


CHO
C - Cl
CH3
SOCl
2

H /Pd-BaSO
2
4

Benzaldehyde
88. Which of the vitamins given below is water soluble?
(A) Vitamin K
(B Vitamin C
(C) Vitamin D
Solution: (B)
Vitamin C is soluble in water.
(D) Vitamin E
89. The colour of KMnO4 is due to:
(A)    * transition
(B) M  L charge transfer transition
(C) d – d transition
(D) L  M charge transfer transition
Solution: (D)
In case of KMnO4 there is absence of vacant d-orbital so. charge transfer spetra from
'L  M' is Responsible for Colour.
90. Two Faraday of electricity is passed through a solution of CuSO4. The mass of copper deposited
at the cathode is (at. mass of Cu  63.5 amu)
(A) 127 g
(B) 0 g
(C) 63.5 g
(D) 2 g
Solution: (C)
Cu2  2e  Cu
2 mole e  is required for depositing 1 mole Cu .
i.e. 2F charge is required for depositing 63.5 gm Cu
7