Sample Question Paper 4 - Chemistry, Class 11 NEET Notes | EduRev

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 Page 1


  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
CBSE 
CLASS – XI 
CHEMISTRY 
SAMPLE PAPER 4 
Time: 3 Hours  Marks: 70 
 
General Instructions 
? All questions are compulsory. 
? Section A: Q.no. 1 to 5 are very short answer questions and carry 1 mark each. 
? Section B: Q.no. 6 to 12 are short answer questions and carry 2 marks each. 
? Section C: Q.no. 13 to 24 are also short answer questions and carry 3 marks each. 
? Section D: Q.no. 25 to 27 are long answer questions and carry 5 marks each. 
? There is no overall choice. However an internal choice has been provided in two 
questions of one mark, two questions of two marks, four questions of three marks 
and all the three questions of five marks weightage. You have to attempt only one of 
the choices in such questions. 
? Use of log tables if necessary, use of calculators is not allowed. 
 
 
Section A 
 
1. Why is an organic compound fused with sodium for testing halogens, nitrogen, sulphur 
and phosphorous?   [1] 
OR 
What kind of isomers are the compounds: CH3CH2OCH2CH3 and CH3OCH2CH2CH3? 
 
2. What shapes are associated with sp
3
d and sp
3
d
2 
hybrid orbitals?                                          [1] 
 
OR 
Arrange the following bonds in the order of increasing ionic character: 
C-H, F-H, Br-H, Na-I, K-F, Li-Cl 
 
3. Although benzene is highly unsaturated it does not undergo addition reactions.     [1] 
 
4. What is siltation? [1] 
 
5. Why alkali and alkaline earth metals cannot be obtained by chemical reduction method?
 [1]  
 
 
 
 
Page 2


  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
CBSE 
CLASS – XI 
CHEMISTRY 
SAMPLE PAPER 4 
Time: 3 Hours  Marks: 70 
 
General Instructions 
? All questions are compulsory. 
? Section A: Q.no. 1 to 5 are very short answer questions and carry 1 mark each. 
? Section B: Q.no. 6 to 12 are short answer questions and carry 2 marks each. 
? Section C: Q.no. 13 to 24 are also short answer questions and carry 3 marks each. 
? Section D: Q.no. 25 to 27 are long answer questions and carry 5 marks each. 
? There is no overall choice. However an internal choice has been provided in two 
questions of one mark, two questions of two marks, four questions of three marks 
and all the three questions of five marks weightage. You have to attempt only one of 
the choices in such questions. 
? Use of log tables if necessary, use of calculators is not allowed. 
 
 
Section A 
 
1. Why is an organic compound fused with sodium for testing halogens, nitrogen, sulphur 
and phosphorous?   [1] 
OR 
What kind of isomers are the compounds: CH3CH2OCH2CH3 and CH3OCH2CH2CH3? 
 
2. What shapes are associated with sp
3
d and sp
3
d
2 
hybrid orbitals?                                          [1] 
 
OR 
Arrange the following bonds in the order of increasing ionic character: 
C-H, F-H, Br-H, Na-I, K-F, Li-Cl 
 
3. Although benzene is highly unsaturated it does not undergo addition reactions.     [1] 
 
4. What is siltation? [1] 
 
5. Why alkali and alkaline earth metals cannot be obtained by chemical reduction method?
 [1]  
 
 
 
 
  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
Section B 
 
6. Which of the following has largest size? Mg, Mg
2+
, Al
3+
,Al                                                        [2]  
7. Consider the following species: [2] 
 N
3-
, O
2-,
 F
–
, Na
+
, Mg
2+,
 Al
3+
 
(a) What is common in them? 
(b) Arrange them in order of increasing ionic radii? 
      
8. The wavelength of first spectral line in Balmer series is 6561 Å. Calculate the wavelength 
of second spectral line in Balmer series.      [2] 
 
9. On a ship sailing in Pacific Ocean where temperature is 23.4°C, a balloon is filled with 2 L 
air. What will be the volume of the balloon when the ship reaches Indian Ocean, where 
temperature is 26.1°C?          
 
10. Balance the following equation in an alkaline medium by half reaction method.       [2] 
           
- - 2-
3 3 4
Cr(OH)   +  IO    I    +  CrO ?  
  OR 
 
11. Give reasons:                [2] 
(a) Anhydrous AlCl3 is covalent but hydrated AlCl3 is electrovalent. Explain 
(b) Boric acid behaves as Lewis acid? Explain  
 
 
12. Which of the two is more concentrated and why? 1 M or 1 m aqueous solution of a 
solute.                      [2] 
 
OR 
 
How many moles and how many grams of NaCl are present in 250 cm
3
 of 0.500 M naCl 
solution? 
 
Section C 
 
13. If the photon of the wavelength 150 pm strikes an atom and one of its inner bound 
electrons is ejected out with a velocity of 1.5 ×10
7
 m/s, calculate the energy with which 
it is bound to the nucleus.              [3]  
 
OR 
 
(a) What are degenerate orbitals? Give examples. 
Page 3


  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
CBSE 
CLASS – XI 
CHEMISTRY 
SAMPLE PAPER 4 
Time: 3 Hours  Marks: 70 
 
General Instructions 
? All questions are compulsory. 
? Section A: Q.no. 1 to 5 are very short answer questions and carry 1 mark each. 
? Section B: Q.no. 6 to 12 are short answer questions and carry 2 marks each. 
? Section C: Q.no. 13 to 24 are also short answer questions and carry 3 marks each. 
? Section D: Q.no. 25 to 27 are long answer questions and carry 5 marks each. 
? There is no overall choice. However an internal choice has been provided in two 
questions of one mark, two questions of two marks, four questions of three marks 
and all the three questions of five marks weightage. You have to attempt only one of 
the choices in such questions. 
? Use of log tables if necessary, use of calculators is not allowed. 
 
 
Section A 
 
1. Why is an organic compound fused with sodium for testing halogens, nitrogen, sulphur 
and phosphorous?   [1] 
OR 
What kind of isomers are the compounds: CH3CH2OCH2CH3 and CH3OCH2CH2CH3? 
 
2. What shapes are associated with sp
3
d and sp
3
d
2 
hybrid orbitals?                                          [1] 
 
OR 
Arrange the following bonds in the order of increasing ionic character: 
C-H, F-H, Br-H, Na-I, K-F, Li-Cl 
 
3. Although benzene is highly unsaturated it does not undergo addition reactions.     [1] 
 
4. What is siltation? [1] 
 
5. Why alkali and alkaline earth metals cannot be obtained by chemical reduction method?
 [1]  
 
 
 
 
  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
Section B 
 
6. Which of the following has largest size? Mg, Mg
2+
, Al
3+
,Al                                                        [2]  
7. Consider the following species: [2] 
 N
3-
, O
2-,
 F
–
, Na
+
, Mg
2+,
 Al
3+
 
(a) What is common in them? 
(b) Arrange them in order of increasing ionic radii? 
      
8. The wavelength of first spectral line in Balmer series is 6561 Å. Calculate the wavelength 
of second spectral line in Balmer series.      [2] 
 
9. On a ship sailing in Pacific Ocean where temperature is 23.4°C, a balloon is filled with 2 L 
air. What will be the volume of the balloon when the ship reaches Indian Ocean, where 
temperature is 26.1°C?          
 
10. Balance the following equation in an alkaline medium by half reaction method.       [2] 
           
- - 2-
3 3 4
Cr(OH)   +  IO    I    +  CrO ?  
  OR 
 
11. Give reasons:                [2] 
(a) Anhydrous AlCl3 is covalent but hydrated AlCl3 is electrovalent. Explain 
(b) Boric acid behaves as Lewis acid? Explain  
 
 
12. Which of the two is more concentrated and why? 1 M or 1 m aqueous solution of a 
solute.                      [2] 
 
OR 
 
How many moles and how many grams of NaCl are present in 250 cm
3
 of 0.500 M naCl 
solution? 
 
Section C 
 
13. If the photon of the wavelength 150 pm strikes an atom and one of its inner bound 
electrons is ejected out with a velocity of 1.5 ×10
7
 m/s, calculate the energy with which 
it is bound to the nucleus.              [3]  
 
OR 
 
(a) What are degenerate orbitals? Give examples. 
  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
(b) Show that the circumference of the Bohr’s orbit for H atom is an integral multiple of 
wavelength associated with the electron revolving aroun the orbit. 
    
 
14. Which out of NH3 and NF3 has higher dipole momemt and why?    [3]  
 
OR 
  
(a) For the complex [Fe(H 2O) 6]
+3
, write the hybridisation, magnetic character and spin of the 
complex. (At, number : Fe = 26) 
(b) Draw one of the geometrical isomers of the complex [Pt (en) 2Cl 2]
+2
 which is optically 
inactive. 
 
 
15. 0.2325g of an organic compound was analysed for nitrogen by Duma’s method. 31.7mL 
of moist nitrogen was collected at 250C and 755.8mm Hg pressure. Calculate the 
percentage of N in the sample. (Aq. Tension of water at 25oC is 23.8mm).       [3]  
 
16. Calculate the enthalpy of combustion of glucose from the following data        [3] 
?
2 2 r
?
2 2 2 r
2 2 6 1
C (graphite) +O CO (g)  ;                                           ? H = -395kJ 
1
H (g) + O (g) H O(l)   ;                                    ? H = -269.4kJ
2
6C (graphite) + 6H (g) + 3O (g) C H
?
?
?
?
2 6 r
O (s) ;       ? H = -1169.9kJ   
 
 
17. Calculate the molar solubility of Ni (OH)2 in 0.10 M NaOH. The solubility product of Ni 
(OH) 2 is 2.0 × 10
-15
.                   [3] 
OR 
 
The pH of 0.1 M solution of cynic acid (HCNO) is 2.34. Calculate the ionization 
constant of the acid and its degree of ionization in the solution. 
 
18.  
(a) Consider the voltaic cell constructed with the following substances:         [3] 
  
? ? ? ?
? ? ? ? ? ? ? ?
3
aq s
42
2 aq aq aq l
o
o
Cr 3e Cr
MnO 8H Se Mn 4H O
E 0.74V
E 1.51V
??
? ? ? ?
??
? ? ? ?
??
??
 
(i) Which substances are oxidised and reduced in this cell? 
(ii) Which are the negative and positive electrodes? 
Page 4


  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
CBSE 
CLASS – XI 
CHEMISTRY 
SAMPLE PAPER 4 
Time: 3 Hours  Marks: 70 
 
General Instructions 
? All questions are compulsory. 
? Section A: Q.no. 1 to 5 are very short answer questions and carry 1 mark each. 
? Section B: Q.no. 6 to 12 are short answer questions and carry 2 marks each. 
? Section C: Q.no. 13 to 24 are also short answer questions and carry 3 marks each. 
? Section D: Q.no. 25 to 27 are long answer questions and carry 5 marks each. 
? There is no overall choice. However an internal choice has been provided in two 
questions of one mark, two questions of two marks, four questions of three marks 
and all the three questions of five marks weightage. You have to attempt only one of 
the choices in such questions. 
? Use of log tables if necessary, use of calculators is not allowed. 
 
 
Section A 
 
1. Why is an organic compound fused with sodium for testing halogens, nitrogen, sulphur 
and phosphorous?   [1] 
OR 
What kind of isomers are the compounds: CH3CH2OCH2CH3 and CH3OCH2CH2CH3? 
 
2. What shapes are associated with sp
3
d and sp
3
d
2 
hybrid orbitals?                                          [1] 
 
OR 
Arrange the following bonds in the order of increasing ionic character: 
C-H, F-H, Br-H, Na-I, K-F, Li-Cl 
 
3. Although benzene is highly unsaturated it does not undergo addition reactions.     [1] 
 
4. What is siltation? [1] 
 
5. Why alkali and alkaline earth metals cannot be obtained by chemical reduction method?
 [1]  
 
 
 
 
  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
Section B 
 
6. Which of the following has largest size? Mg, Mg
2+
, Al
3+
,Al                                                        [2]  
7. Consider the following species: [2] 
 N
3-
, O
2-,
 F
–
, Na
+
, Mg
2+,
 Al
3+
 
(a) What is common in them? 
(b) Arrange them in order of increasing ionic radii? 
      
8. The wavelength of first spectral line in Balmer series is 6561 Å. Calculate the wavelength 
of second spectral line in Balmer series.      [2] 
 
9. On a ship sailing in Pacific Ocean where temperature is 23.4°C, a balloon is filled with 2 L 
air. What will be the volume of the balloon when the ship reaches Indian Ocean, where 
temperature is 26.1°C?          
 
10. Balance the following equation in an alkaline medium by half reaction method.       [2] 
           
- - 2-
3 3 4
Cr(OH)   +  IO    I    +  CrO ?  
  OR 
 
11. Give reasons:                [2] 
(a) Anhydrous AlCl3 is covalent but hydrated AlCl3 is electrovalent. Explain 
(b) Boric acid behaves as Lewis acid? Explain  
 
 
12. Which of the two is more concentrated and why? 1 M or 1 m aqueous solution of a 
solute.                      [2] 
 
OR 
 
How many moles and how many grams of NaCl are present in 250 cm
3
 of 0.500 M naCl 
solution? 
 
Section C 
 
13. If the photon of the wavelength 150 pm strikes an atom and one of its inner bound 
electrons is ejected out with a velocity of 1.5 ×10
7
 m/s, calculate the energy with which 
it is bound to the nucleus.              [3]  
 
OR 
 
(a) What are degenerate orbitals? Give examples. 
  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
(b) Show that the circumference of the Bohr’s orbit for H atom is an integral multiple of 
wavelength associated with the electron revolving aroun the orbit. 
    
 
14. Which out of NH3 and NF3 has higher dipole momemt and why?    [3]  
 
OR 
  
(a) For the complex [Fe(H 2O) 6]
+3
, write the hybridisation, magnetic character and spin of the 
complex. (At, number : Fe = 26) 
(b) Draw one of the geometrical isomers of the complex [Pt (en) 2Cl 2]
+2
 which is optically 
inactive. 
 
 
15. 0.2325g of an organic compound was analysed for nitrogen by Duma’s method. 31.7mL 
of moist nitrogen was collected at 250C and 755.8mm Hg pressure. Calculate the 
percentage of N in the sample. (Aq. Tension of water at 25oC is 23.8mm).       [3]  
 
16. Calculate the enthalpy of combustion of glucose from the following data        [3] 
?
2 2 r
?
2 2 2 r
2 2 6 1
C (graphite) +O CO (g)  ;                                           ? H = -395kJ 
1
H (g) + O (g) H O(l)   ;                                    ? H = -269.4kJ
2
6C (graphite) + 6H (g) + 3O (g) C H
?
?
?
?
2 6 r
O (s) ;       ? H = -1169.9kJ   
 
 
17. Calculate the molar solubility of Ni (OH)2 in 0.10 M NaOH. The solubility product of Ni 
(OH) 2 is 2.0 × 10
-15
.                   [3] 
OR 
 
The pH of 0.1 M solution of cynic acid (HCNO) is 2.34. Calculate the ionization 
constant of the acid and its degree of ionization in the solution. 
 
18.  
(a) Consider the voltaic cell constructed with the following substances:         [3] 
  
? ? ? ?
? ? ? ? ? ? ? ?
3
aq s
42
2 aq aq aq l
o
o
Cr 3e Cr
MnO 8H Se Mn 4H O
E 0.74V
E 1.51V
??
? ? ? ?
??
? ? ? ?
??
??
 
(i) Which substances are oxidised and reduced in this cell? 
(ii) Which are the negative and positive electrodes? 
  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
(b) Write the oxidation number of the following atoms: 
(i) KMnO4 
(ii) K2Cr2O7 
 
OR 
 
Write the half reactions for each of the following redox reactions: 
          
? ?
? ?
? ? ? ? ? ?
? ?
? ?
? ?
( s )
s
2
sa ( ) ( ) ( ) (g)
3
aq a
q aq
qs
( ) 2 g
2
2 s
A
a      Zn 2H
l 3Ag Al 3Ag
c Mg
 Zn   H
b    
Cl MgCl
 
??
??
? ? ?
??
? ? ?
 
 
19. Arrange the following:           [3] 
(a) CaH2, BeH2 and TiH2 in order of increasing electrical conductance. 
(b) LiH, NaH and CsH in order of increasing ionic character. 
(c) H?H, D?D and F?F in order of increasing bond dissociation enthalpy. 
 
20.                  [3] 
(a)  Why cannot sulphuric acid be used to acidify sodium extract for testing S using 
lead acetate solution? 
(b) Which of the carbocations is most stable and why? 
       
3 3 3 2 2 3 2 3
            +                        +                    +            
  (CH ) C   ,   CH CH CH  ,    CH CHCH CH
 
(c) Why does a liquid vaporize below its boiling point in steam distillation process? 
 
21. What type of isomerism is exhibited by following pair of compounds?    [3] 
(i) Ethanol and Methoxy methane 
(ii) o-cresol and m-cresol 
(iii) Pentan-3-one and pentan-2-one 
 
22. Explain                                                                                                                                              [3]                                                                                            
(a) Fish do not grow as well in warm water as in cold water. Why? 
(b) Why does rain water normally have a pH about 5.6? 
(c) Name two major greenhouse gases. 
 
23. Write the IUPAC names of the following compounds:     [3] 
(a) CH3CH?C(CH3)2 
(b)  
 
Page 5


  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
CBSE 
CLASS – XI 
CHEMISTRY 
SAMPLE PAPER 4 
Time: 3 Hours  Marks: 70 
 
General Instructions 
? All questions are compulsory. 
? Section A: Q.no. 1 to 5 are very short answer questions and carry 1 mark each. 
? Section B: Q.no. 6 to 12 are short answer questions and carry 2 marks each. 
? Section C: Q.no. 13 to 24 are also short answer questions and carry 3 marks each. 
? Section D: Q.no. 25 to 27 are long answer questions and carry 5 marks each. 
? There is no overall choice. However an internal choice has been provided in two 
questions of one mark, two questions of two marks, four questions of three marks 
and all the three questions of five marks weightage. You have to attempt only one of 
the choices in such questions. 
? Use of log tables if necessary, use of calculators is not allowed. 
 
 
Section A 
 
1. Why is an organic compound fused with sodium for testing halogens, nitrogen, sulphur 
and phosphorous?   [1] 
OR 
What kind of isomers are the compounds: CH3CH2OCH2CH3 and CH3OCH2CH2CH3? 
 
2. What shapes are associated with sp
3
d and sp
3
d
2 
hybrid orbitals?                                          [1] 
 
OR 
Arrange the following bonds in the order of increasing ionic character: 
C-H, F-H, Br-H, Na-I, K-F, Li-Cl 
 
3. Although benzene is highly unsaturated it does not undergo addition reactions.     [1] 
 
4. What is siltation? [1] 
 
5. Why alkali and alkaline earth metals cannot be obtained by chemical reduction method?
 [1]  
 
 
 
 
  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
Section B 
 
6. Which of the following has largest size? Mg, Mg
2+
, Al
3+
,Al                                                        [2]  
7. Consider the following species: [2] 
 N
3-
, O
2-,
 F
–
, Na
+
, Mg
2+,
 Al
3+
 
(a) What is common in them? 
(b) Arrange them in order of increasing ionic radii? 
      
8. The wavelength of first spectral line in Balmer series is 6561 Å. Calculate the wavelength 
of second spectral line in Balmer series.      [2] 
 
9. On a ship sailing in Pacific Ocean where temperature is 23.4°C, a balloon is filled with 2 L 
air. What will be the volume of the balloon when the ship reaches Indian Ocean, where 
temperature is 26.1°C?          
 
10. Balance the following equation in an alkaline medium by half reaction method.       [2] 
           
- - 2-
3 3 4
Cr(OH)   +  IO    I    +  CrO ?  
  OR 
 
11. Give reasons:                [2] 
(a) Anhydrous AlCl3 is covalent but hydrated AlCl3 is electrovalent. Explain 
(b) Boric acid behaves as Lewis acid? Explain  
 
 
12. Which of the two is more concentrated and why? 1 M or 1 m aqueous solution of a 
solute.                      [2] 
 
OR 
 
How many moles and how many grams of NaCl are present in 250 cm
3
 of 0.500 M naCl 
solution? 
 
Section C 
 
13. If the photon of the wavelength 150 pm strikes an atom and one of its inner bound 
electrons is ejected out with a velocity of 1.5 ×10
7
 m/s, calculate the energy with which 
it is bound to the nucleus.              [3]  
 
OR 
 
(a) What are degenerate orbitals? Give examples. 
  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
(b) Show that the circumference of the Bohr’s orbit for H atom is an integral multiple of 
wavelength associated with the electron revolving aroun the orbit. 
    
 
14. Which out of NH3 and NF3 has higher dipole momemt and why?    [3]  
 
OR 
  
(a) For the complex [Fe(H 2O) 6]
+3
, write the hybridisation, magnetic character and spin of the 
complex. (At, number : Fe = 26) 
(b) Draw one of the geometrical isomers of the complex [Pt (en) 2Cl 2]
+2
 which is optically 
inactive. 
 
 
15. 0.2325g of an organic compound was analysed for nitrogen by Duma’s method. 31.7mL 
of moist nitrogen was collected at 250C and 755.8mm Hg pressure. Calculate the 
percentage of N in the sample. (Aq. Tension of water at 25oC is 23.8mm).       [3]  
 
16. Calculate the enthalpy of combustion of glucose from the following data        [3] 
?
2 2 r
?
2 2 2 r
2 2 6 1
C (graphite) +O CO (g)  ;                                           ? H = -395kJ 
1
H (g) + O (g) H O(l)   ;                                    ? H = -269.4kJ
2
6C (graphite) + 6H (g) + 3O (g) C H
?
?
?
?
2 6 r
O (s) ;       ? H = -1169.9kJ   
 
 
17. Calculate the molar solubility of Ni (OH)2 in 0.10 M NaOH. The solubility product of Ni 
(OH) 2 is 2.0 × 10
-15
.                   [3] 
OR 
 
The pH of 0.1 M solution of cynic acid (HCNO) is 2.34. Calculate the ionization 
constant of the acid and its degree of ionization in the solution. 
 
18.  
(a) Consider the voltaic cell constructed with the following substances:         [3] 
  
? ? ? ?
? ? ? ? ? ? ? ?
3
aq s
42
2 aq aq aq l
o
o
Cr 3e Cr
MnO 8H Se Mn 4H O
E 0.74V
E 1.51V
??
? ? ? ?
??
? ? ? ?
??
??
 
(i) Which substances are oxidised and reduced in this cell? 
(ii) Which are the negative and positive electrodes? 
  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
(b) Write the oxidation number of the following atoms: 
(i) KMnO4 
(ii) K2Cr2O7 
 
OR 
 
Write the half reactions for each of the following redox reactions: 
          
? ?
? ?
? ? ? ? ? ?
? ?
? ?
? ?
( s )
s
2
sa ( ) ( ) ( ) (g)
3
aq a
q aq
qs
( ) 2 g
2
2 s
A
a      Zn 2H
l 3Ag Al 3Ag
c Mg
 Zn   H
b    
Cl MgCl
 
??
??
? ? ?
??
? ? ?
 
 
19. Arrange the following:           [3] 
(a) CaH2, BeH2 and TiH2 in order of increasing electrical conductance. 
(b) LiH, NaH and CsH in order of increasing ionic character. 
(c) H?H, D?D and F?F in order of increasing bond dissociation enthalpy. 
 
20.                  [3] 
(a)  Why cannot sulphuric acid be used to acidify sodium extract for testing S using 
lead acetate solution? 
(b) Which of the carbocations is most stable and why? 
       
3 3 3 2 2 3 2 3
            +                        +                    +            
  (CH ) C   ,   CH CH CH  ,    CH CHCH CH
 
(c) Why does a liquid vaporize below its boiling point in steam distillation process? 
 
21. What type of isomerism is exhibited by following pair of compounds?    [3] 
(i) Ethanol and Methoxy methane 
(ii) o-cresol and m-cresol 
(iii) Pentan-3-one and pentan-2-one 
 
22. Explain                                                                                                                                              [3]                                                                                            
(a) Fish do not grow as well in warm water as in cold water. Why? 
(b) Why does rain water normally have a pH about 5.6? 
(c) Name two major greenhouse gases. 
 
23. Write the IUPAC names of the following compounds:     [3] 
(a) CH3CH?C(CH3)2 
(b)  
 
  
 
CBSE XI | Chemistry 
Sample Paper – 4 
 
    
 
(c)  
 
 
24. When a metal X is treated with sodium hydroxide, a white precipitate A is obtained, 
which is soluble in an excess of NaOH to give soluble complex B. Compound A is 
soluble in diluted HCl to form compound C. The compound A when heated strongly 
gives D, which is used to extract metal. Identify X, A, B, C and D. Write suitable 
equations to support their identities.              [3] 
 
 
 Section D 
 
25.                   [5] 
(a) What is spontaneous change? What is the condition for spontaneity in terms of free energy 
change? 
(b) At 60°C, dinitrogen tetroxide is fifty percent dissociated. Calculate the standard free energy 
change at this temperature and at one atmosphere.             
       
OR 
(a)  
(i) Why standard enthalpy of an elementary substance is not zero wheras standard 
enthalpy of formation is taken as zero? 
(ii) Under what conditions will the reaction occur, if, 
Both ?H and ?S are positive 
Both ?H and ?S are negative 
   
(b) Calculate the enthalpy change for the reaction : 
H2(g) + Cl(2)(g)
 ?
  2HCl (g) 
Given that bond energies of H-H, Cl-Cl and H-Cl bonds are 433, 244 and 431 kJ/mol 
respectively. 
               
26. Give reasons for the following          [5] 
(a) Unlike Na2CO3, K2CO3 cannot be prepared by Solvay process. Why? 
(b) Why are alkali metals not found in nature? 
(c) Sodium is less reactive than potassium why? 
(d) Alkali metals are good reducing agents. Why? 
(e) Alkali metals are paramagnetic but their salts are diamagnetic. Why? 
   
OR 
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Objective type Questions

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Previous Year Questions with Solutions

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shortcuts and tricks

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past year papers

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practice quizzes

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Semester Notes

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study material

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Sample Question Paper 4 - Chemistry

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Summary

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video lectures

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Extra Questions

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Class 11 NEET Notes | EduRev

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Viva Questions

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mock tests for examination

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