Page 1
CBSE XI | Chemistry
Sample Paper – 1 Solution
CBSE
Class XI Chemistry
Sample Paper – 1 Solution
Section A
1. This is because o – nitro phenol has intramolecular hydrogen bonding whereas p- nitro
phenol has intermolecular hydrogen bonding.
OR
-
2 2 2
O NCH CH O will be more stable because
2
-NO group has electron withdrawing inductive
effect or – I effect.
2. CO2 has a larger bond angle than
3
BF . This is because
2
CO has a linear shape and the
bond angle is 180
o
,
3
BF on the other hand has a trigonal planar geometry and hence the
bond angle is 120
o
.
OR
Bond order of N2 is greater than that of O2. Higher is the bond order greater is the
stability. Therefore N2 is more stable than O2.
3. The eclipsed conformation of propane is less stable and has more energy than the
eclipsed conformation of ethane. This is because in propane there are additional
interactions between C-H and C-C bond of methyl group.
4. In Antarctica, ozone depletion is due to the formation of chlorine nitrate.
5. Alkali metals have low ionization energies. They can lose electrons when light falls on
them, and hence are used in photo electric cells.
Section B
6. Statement ‘a’ is correct and b is incorrect.
Statement ‘b’ is incorrect because d sub shell can have a maximum of 10 electrons.
Therefore it has 10 columns and not 8.
7. Elements in which transition of electrons to higher energy d-orbital cannot take place
are not transition elements. Thus, elements like Zn, Cd and Hg in which all the d-orbitals
are completely filled are not transition elements although they have been grouped with
d-block.
Page 2
CBSE XI | Chemistry
Sample Paper – 1 Solution
CBSE
Class XI Chemistry
Sample Paper – 1 Solution
Section A
1. This is because o – nitro phenol has intramolecular hydrogen bonding whereas p- nitro
phenol has intermolecular hydrogen bonding.
OR
-
2 2 2
O NCH CH O will be more stable because
2
-NO group has electron withdrawing inductive
effect or – I effect.
2. CO2 has a larger bond angle than
3
BF . This is because
2
CO has a linear shape and the
bond angle is 180
o
,
3
BF on the other hand has a trigonal planar geometry and hence the
bond angle is 120
o
.
OR
Bond order of N2 is greater than that of O2. Higher is the bond order greater is the
stability. Therefore N2 is more stable than O2.
3. The eclipsed conformation of propane is less stable and has more energy than the
eclipsed conformation of ethane. This is because in propane there are additional
interactions between C-H and C-C bond of methyl group.
4. In Antarctica, ozone depletion is due to the formation of chlorine nitrate.
5. Alkali metals have low ionization energies. They can lose electrons when light falls on
them, and hence are used in photo electric cells.
Section B
6. Statement ‘a’ is correct and b is incorrect.
Statement ‘b’ is incorrect because d sub shell can have a maximum of 10 electrons.
Therefore it has 10 columns and not 8.
7. Elements in which transition of electrons to higher energy d-orbital cannot take place
are not transition elements. Thus, elements like Zn, Cd and Hg in which all the d-orbitals
are completely filled are not transition elements although they have been grouped with
d-block.
CBSE XI | Chemistry
Sample Paper – 1 Solution
8. Given:
9
8
8
9
14 1
14
456nm
456 10 m
c 3 10 m / s
Wehave,
c
3 10
456 10
6.5 10 s
6.5 10 Hz
?
?
?
??
??
??
??
?
?
?
?
? ? ?
? ? ?
Frequency is 6.5×10
14
Hz
9. Oxidation number of Pb in PbO is +2 while in PbO2 it is +4. This causes the compounds to
differ in their reactivity. While PbO reacts with HCl to give acid-base reaction, and PbO2
reacts with HCl to give redox reaction.
2PbO + 4HCl ? 2PbCl2 + 2H2O (acid-base reaction)
PbO2 + 4HCl ? PbCl2 + Cl2 + 2H2O (redox reaction)
10.
? ? ? ?
2 2 2
2H O+ 2 F 4HF +O
F2 is the oxidizing agent and H2O is reducing agent.
H2O is getting oxidized to O2 whereas F2 is getting reduced to F
-
ion.
OR
(a) PbS(g) + H2O2(aq) ? PbSO4(s) + 4H2O(l)
(b) CO(g) + 2 H2(g)
Cobalt
catalyst
? ? ? ? CH3OH
11. The energy required to excite outer electrons in the atoms of Be and Mg does not lie in
the visible range of radiation. Therefore, no absorption of radiation takes place and
hence no colour is imparted to the flame in the flame test.
Page 3
CBSE XI | Chemistry
Sample Paper – 1 Solution
CBSE
Class XI Chemistry
Sample Paper – 1 Solution
Section A
1. This is because o – nitro phenol has intramolecular hydrogen bonding whereas p- nitro
phenol has intermolecular hydrogen bonding.
OR
-
2 2 2
O NCH CH O will be more stable because
2
-NO group has electron withdrawing inductive
effect or – I effect.
2. CO2 has a larger bond angle than
3
BF . This is because
2
CO has a linear shape and the
bond angle is 180
o
,
3
BF on the other hand has a trigonal planar geometry and hence the
bond angle is 120
o
.
OR
Bond order of N2 is greater than that of O2. Higher is the bond order greater is the
stability. Therefore N2 is more stable than O2.
3. The eclipsed conformation of propane is less stable and has more energy than the
eclipsed conformation of ethane. This is because in propane there are additional
interactions between C-H and C-C bond of methyl group.
4. In Antarctica, ozone depletion is due to the formation of chlorine nitrate.
5. Alkali metals have low ionization energies. They can lose electrons when light falls on
them, and hence are used in photo electric cells.
Section B
6. Statement ‘a’ is correct and b is incorrect.
Statement ‘b’ is incorrect because d sub shell can have a maximum of 10 electrons.
Therefore it has 10 columns and not 8.
7. Elements in which transition of electrons to higher energy d-orbital cannot take place
are not transition elements. Thus, elements like Zn, Cd and Hg in which all the d-orbitals
are completely filled are not transition elements although they have been grouped with
d-block.
CBSE XI | Chemistry
Sample Paper – 1 Solution
8. Given:
9
8
8
9
14 1
14
456nm
456 10 m
c 3 10 m / s
Wehave,
c
3 10
456 10
6.5 10 s
6.5 10 Hz
?
?
?
??
??
??
??
?
?
?
?
? ? ?
? ? ?
Frequency is 6.5×10
14
Hz
9. Oxidation number of Pb in PbO is +2 while in PbO2 it is +4. This causes the compounds to
differ in their reactivity. While PbO reacts with HCl to give acid-base reaction, and PbO2
reacts with HCl to give redox reaction.
2PbO + 4HCl ? 2PbCl2 + 2H2O (acid-base reaction)
PbO2 + 4HCl ? PbCl2 + Cl2 + 2H2O (redox reaction)
10.
? ? ? ?
2 2 2
2H O+ 2 F 4HF +O
F2 is the oxidizing agent and H2O is reducing agent.
H2O is getting oxidized to O2 whereas F2 is getting reduced to F
-
ion.
OR
(a) PbS(g) + H2O2(aq) ? PbSO4(s) + 4H2O(l)
(b) CO(g) + 2 H2(g)
Cobalt
catalyst
? ? ? ? CH3OH
11. The energy required to excite outer electrons in the atoms of Be and Mg does not lie in
the visible range of radiation. Therefore, no absorption of radiation takes place and
hence no colour is imparted to the flame in the flame test.
CBSE XI | Chemistry
Sample Paper – 1 Solution
12.
? ? ? ?
24
Massof element in that compound
Mass % of anelement 100
Molarmassof thecompound
Molarmassof Na SO 2 23 32 4 16
142g / mol
46
Mass % of Na 100
142
32.39%
32
Mass % of S 100
142
22.54%
64
Mass % of O 100
142
45.07%
??
? ? ?
?
??
?
??
?
??
?
OR
Given:
Weight of CuSO4 =100 g
Atomic mass of Cu – 63.5 amu
1 mole of CuSO4 contains 1 mole of Cu
Molar mass of CuSO4 = 63.5 + 32+ (4×16)
= 159.5 g/mol
So, Cu that can be obtained from 159.5 g of CuSO4 = 63.5 g
Therefore, Cu that can be obtained from 100 g of CuSO4
63.5
100
159.5
39.81g
??
?
Page 4
CBSE XI | Chemistry
Sample Paper – 1 Solution
CBSE
Class XI Chemistry
Sample Paper – 1 Solution
Section A
1. This is because o – nitro phenol has intramolecular hydrogen bonding whereas p- nitro
phenol has intermolecular hydrogen bonding.
OR
-
2 2 2
O NCH CH O will be more stable because
2
-NO group has electron withdrawing inductive
effect or – I effect.
2. CO2 has a larger bond angle than
3
BF . This is because
2
CO has a linear shape and the
bond angle is 180
o
,
3
BF on the other hand has a trigonal planar geometry and hence the
bond angle is 120
o
.
OR
Bond order of N2 is greater than that of O2. Higher is the bond order greater is the
stability. Therefore N2 is more stable than O2.
3. The eclipsed conformation of propane is less stable and has more energy than the
eclipsed conformation of ethane. This is because in propane there are additional
interactions between C-H and C-C bond of methyl group.
4. In Antarctica, ozone depletion is due to the formation of chlorine nitrate.
5. Alkali metals have low ionization energies. They can lose electrons when light falls on
them, and hence are used in photo electric cells.
Section B
6. Statement ‘a’ is correct and b is incorrect.
Statement ‘b’ is incorrect because d sub shell can have a maximum of 10 electrons.
Therefore it has 10 columns and not 8.
7. Elements in which transition of electrons to higher energy d-orbital cannot take place
are not transition elements. Thus, elements like Zn, Cd and Hg in which all the d-orbitals
are completely filled are not transition elements although they have been grouped with
d-block.
CBSE XI | Chemistry
Sample Paper – 1 Solution
8. Given:
9
8
8
9
14 1
14
456nm
456 10 m
c 3 10 m / s
Wehave,
c
3 10
456 10
6.5 10 s
6.5 10 Hz
?
?
?
??
??
??
??
?
?
?
?
? ? ?
? ? ?
Frequency is 6.5×10
14
Hz
9. Oxidation number of Pb in PbO is +2 while in PbO2 it is +4. This causes the compounds to
differ in their reactivity. While PbO reacts with HCl to give acid-base reaction, and PbO2
reacts with HCl to give redox reaction.
2PbO + 4HCl ? 2PbCl2 + 2H2O (acid-base reaction)
PbO2 + 4HCl ? PbCl2 + Cl2 + 2H2O (redox reaction)
10.
? ? ? ?
2 2 2
2H O+ 2 F 4HF +O
F2 is the oxidizing agent and H2O is reducing agent.
H2O is getting oxidized to O2 whereas F2 is getting reduced to F
-
ion.
OR
(a) PbS(g) + H2O2(aq) ? PbSO4(s) + 4H2O(l)
(b) CO(g) + 2 H2(g)
Cobalt
catalyst
? ? ? ? CH3OH
11. The energy required to excite outer electrons in the atoms of Be and Mg does not lie in
the visible range of radiation. Therefore, no absorption of radiation takes place and
hence no colour is imparted to the flame in the flame test.
CBSE XI | Chemistry
Sample Paper – 1 Solution
12.
? ? ? ?
24
Massof element in that compound
Mass % of anelement 100
Molarmassof thecompound
Molarmassof Na SO 2 23 32 4 16
142g / mol
46
Mass % of Na 100
142
32.39%
32
Mass % of S 100
142
22.54%
64
Mass % of O 100
142
45.07%
??
? ? ?
?
??
?
??
?
??
?
OR
Given:
Weight of CuSO4 =100 g
Atomic mass of Cu – 63.5 amu
1 mole of CuSO4 contains 1 mole of Cu
Molar mass of CuSO4 = 63.5 + 32+ (4×16)
= 159.5 g/mol
So, Cu that can be obtained from 159.5 g of CuSO4 = 63.5 g
Therefore, Cu that can be obtained from 100 g of CuSO4
63.5
100
159.5
39.81g
??
?
CBSE XI | Chemistry
Sample Paper – 1 Solution
13.
(a) The 4f sub shell of an atom contains 12 electrons
4f
12
?? ??
??
??
??
?
?
So maximum 7 electrons will have same spin.
(b) Six electrons are filled in three orbitals of 4p subshell.
4p
6
?? ??
??
(c) Z =29
Electronic configuration
2 2 6 2 6 10 1
1s 2s 2p 3s 3p 3d 4s
OR
(a) Number of electrons in 1 molecule of methane = 6 + 4 =10 electrons
Number of molecules in 1 mole of methane
23
= 6.022 × 10 molecules of methane
Number of electrons in 1 mole of methane
23
24
= 6.022×10 10
= 6.0 electr 22×10 ons
?
(b) n = 3
? ? 0 -1
0,1,2
?
?
l to n
For 0 ? l ,
0 ?
l
m
For 1 ? l
1, 0, 1 ? ? ?
l
m
For 2 l ?
2, 1, 0, 1, 2 ? ? ? ? ?
l
m
Page 5
CBSE XI | Chemistry
Sample Paper – 1 Solution
CBSE
Class XI Chemistry
Sample Paper – 1 Solution
Section A
1. This is because o – nitro phenol has intramolecular hydrogen bonding whereas p- nitro
phenol has intermolecular hydrogen bonding.
OR
-
2 2 2
O NCH CH O will be more stable because
2
-NO group has electron withdrawing inductive
effect or – I effect.
2. CO2 has a larger bond angle than
3
BF . This is because
2
CO has a linear shape and the
bond angle is 180
o
,
3
BF on the other hand has a trigonal planar geometry and hence the
bond angle is 120
o
.
OR
Bond order of N2 is greater than that of O2. Higher is the bond order greater is the
stability. Therefore N2 is more stable than O2.
3. The eclipsed conformation of propane is less stable and has more energy than the
eclipsed conformation of ethane. This is because in propane there are additional
interactions between C-H and C-C bond of methyl group.
4. In Antarctica, ozone depletion is due to the formation of chlorine nitrate.
5. Alkali metals have low ionization energies. They can lose electrons when light falls on
them, and hence are used in photo electric cells.
Section B
6. Statement ‘a’ is correct and b is incorrect.
Statement ‘b’ is incorrect because d sub shell can have a maximum of 10 electrons.
Therefore it has 10 columns and not 8.
7. Elements in which transition of electrons to higher energy d-orbital cannot take place
are not transition elements. Thus, elements like Zn, Cd and Hg in which all the d-orbitals
are completely filled are not transition elements although they have been grouped with
d-block.
CBSE XI | Chemistry
Sample Paper – 1 Solution
8. Given:
9
8
8
9
14 1
14
456nm
456 10 m
c 3 10 m / s
Wehave,
c
3 10
456 10
6.5 10 s
6.5 10 Hz
?
?
?
??
??
??
??
?
?
?
?
? ? ?
? ? ?
Frequency is 6.5×10
14
Hz
9. Oxidation number of Pb in PbO is +2 while in PbO2 it is +4. This causes the compounds to
differ in their reactivity. While PbO reacts with HCl to give acid-base reaction, and PbO2
reacts with HCl to give redox reaction.
2PbO + 4HCl ? 2PbCl2 + 2H2O (acid-base reaction)
PbO2 + 4HCl ? PbCl2 + Cl2 + 2H2O (redox reaction)
10.
? ? ? ?
2 2 2
2H O+ 2 F 4HF +O
F2 is the oxidizing agent and H2O is reducing agent.
H2O is getting oxidized to O2 whereas F2 is getting reduced to F
-
ion.
OR
(a) PbS(g) + H2O2(aq) ? PbSO4(s) + 4H2O(l)
(b) CO(g) + 2 H2(g)
Cobalt
catalyst
? ? ? ? CH3OH
11. The energy required to excite outer electrons in the atoms of Be and Mg does not lie in
the visible range of radiation. Therefore, no absorption of radiation takes place and
hence no colour is imparted to the flame in the flame test.
CBSE XI | Chemistry
Sample Paper – 1 Solution
12.
? ? ? ?
24
Massof element in that compound
Mass % of anelement 100
Molarmassof thecompound
Molarmassof Na SO 2 23 32 4 16
142g / mol
46
Mass % of Na 100
142
32.39%
32
Mass % of S 100
142
22.54%
64
Mass % of O 100
142
45.07%
??
? ? ?
?
??
?
??
?
??
?
OR
Given:
Weight of CuSO4 =100 g
Atomic mass of Cu – 63.5 amu
1 mole of CuSO4 contains 1 mole of Cu
Molar mass of CuSO4 = 63.5 + 32+ (4×16)
= 159.5 g/mol
So, Cu that can be obtained from 159.5 g of CuSO4 = 63.5 g
Therefore, Cu that can be obtained from 100 g of CuSO4
63.5
100
159.5
39.81g
??
?
CBSE XI | Chemistry
Sample Paper – 1 Solution
13.
(a) The 4f sub shell of an atom contains 12 electrons
4f
12
?? ??
??
??
??
?
?
So maximum 7 electrons will have same spin.
(b) Six electrons are filled in three orbitals of 4p subshell.
4p
6
?? ??
??
(c) Z =29
Electronic configuration
2 2 6 2 6 10 1
1s 2s 2p 3s 3p 3d 4s
OR
(a) Number of electrons in 1 molecule of methane = 6 + 4 =10 electrons
Number of molecules in 1 mole of methane
23
= 6.022 × 10 molecules of methane
Number of electrons in 1 mole of methane
23
24
= 6.022×10 10
= 6.0 electr 22×10 ons
?
(b) n = 3
? ? 0 -1
0,1,2
?
?
l to n
For 0 ? l ,
0 ?
l
m
For 1 ? l
1, 0, 1 ? ? ?
l
m
For 2 l ?
2, 1, 0, 1, 2 ? ? ? ? ?
l
m
CBSE XI | Chemistry
Sample Paper – 1 Solution
14. The electronic configuration of
2 2 6 2 4
S=1s 2s 2p 3s 3p
1s 2s 2p 3s 3p
Ground state
1s 2s 2p 3s 3p 3d
Excited State
Sp
3
hybridisation
1s 2s 2p sp
3
d sp
3
d sp
3
d sp
3
d sp
3
d 3d
Hybridise State
Sulphur undergoes sp
3
d hybridisation.
OR
(a) In CO2 there are two C=O bond. Each C=O bond is polar bond. The net dipole moment
of CO2 molecule is zero. This is possible only if CO2 is a linear molecule (O=C=O). The
bond dipoles of two C=O bond cancel with each other.
Whereas H2O molecule has a net dipole moment (1.84 D) H2O molecule has a bent
structure because here the O-H bonds are oriented at an angle of 104.5
°
and do not
cancel the bond moments of each other.
(b) Significance/applications of dipole moment-
i) In predicting the nature of the molecules: Molecules with specific dipole moments
are polar in nature and those of zero dipole moments are non-polar in nature.
ii) In the determination of shapes of molecules.
iii) In calculating the percentage ionic character.
??
??
??
?? ??
??
?? ?? ??
??
??
??
?? ?? ??
?? ?? ??
?
??
??
??
? ? ? ? ??
?? ??
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