Sample Question Paper 3: Chemistry, Class 11 | Chemistry for Grade 11 PDF Download

 Page 1


  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
CBSE 
CLASS – XI 
CHEMISTRY 
SAMPLE PAPER 3 
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. Arrange the following in the order of decreasing reactivity towards alkenes.   [1] 
 HCl, HBr, HI, HF 
 
2. Predict the shapes of the following molecules using VSEPR theory? 
   BeCl2, SiCl4  [1] 
 
OR 
 
      What is meant by bond pairs of electrons? 
 
3. Give IUPAC name of allyl alcohol. [1] 
 
4. What is biochemical oxygen demand?   [1] 
 
OR 
 
What is the name of the compound formed when CO combines with blood? 
 
 
5. Give the colours shown in the flame test by sodium and potassium.  [1] 
 
Page 2


  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
CBSE 
CLASS – XI 
CHEMISTRY 
SAMPLE PAPER 3 
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. Arrange the following in the order of decreasing reactivity towards alkenes.   [1] 
 HCl, HBr, HI, HF 
 
2. Predict the shapes of the following molecules using VSEPR theory? 
   BeCl2, SiCl4  [1] 
 
OR 
 
      What is meant by bond pairs of electrons? 
 
3. Give IUPAC name of allyl alcohol. [1] 
 
4. What is biochemical oxygen demand?   [1] 
 
OR 
 
What is the name of the compound formed when CO combines with blood? 
 
 
5. Give the colours shown in the flame test by sodium and potassium.  [1] 
 
  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
Section B 
 
6. How does metallic and nonmetallic character vary on moving from left to right in the 
periodic table? [2] 
     
7. Arrange the following in increasing order of size. Give reason for your answer.   [2] 
            Mg
2+        
O
2-          
Na
+
     F
-
         Al
3+              
.    
   
8. Calculate the wavelength of an electron moving with a velocity of 2.05 x 10
7
m/s.   
 (Mass of electron = 9.1 x 10
-31
kg, h =6.63 x 10
-34
Js)     [2] 
 
9. At 273 K the density of a gaseous oxide at 2 bar is the same as that of nitrogen      
(Atomic mass =14u) at 5 bar. Calculate the molar mass of the oxide  [2]        
      
10. Consider the reaction of water with F2 and suggest, in terms of oxidation and       
reduction, which species are oxidized/ reduced.            [2] 
  
  OR 
Complete the following reactions: 
(a) PbS(g) + H2O2(aq)   ?  
(b) CO(g) + 2 H2(g) 
Cobalt
catalyst
? ? ? ?  
 
11. How many neutrons and protons are there in following nuclei?                                   [2] 
            
            (a)
56
26
Fe 
            (b) 
88
38
Sr 
 
12. If density of methanol is 0.793 kg/L, what is its volume needed for making 2.5 L of its 
0.25 M solution?                   [2] 
 
OR 
 
The density of 3 M solution of NaCl is 1.25 g/ml. Calculate the molarity of the solution. 
  
Page 3


  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
CBSE 
CLASS – XI 
CHEMISTRY 
SAMPLE PAPER 3 
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. Arrange the following in the order of decreasing reactivity towards alkenes.   [1] 
 HCl, HBr, HI, HF 
 
2. Predict the shapes of the following molecules using VSEPR theory? 
   BeCl2, SiCl4  [1] 
 
OR 
 
      What is meant by bond pairs of electrons? 
 
3. Give IUPAC name of allyl alcohol. [1] 
 
4. What is biochemical oxygen demand?   [1] 
 
OR 
 
What is the name of the compound formed when CO combines with blood? 
 
 
5. Give the colours shown in the flame test by sodium and potassium.  [1] 
 
  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
Section B 
 
6. How does metallic and nonmetallic character vary on moving from left to right in the 
periodic table? [2] 
     
7. Arrange the following in increasing order of size. Give reason for your answer.   [2] 
            Mg
2+        
O
2-          
Na
+
     F
-
         Al
3+              
.    
   
8. Calculate the wavelength of an electron moving with a velocity of 2.05 x 10
7
m/s.   
 (Mass of electron = 9.1 x 10
-31
kg, h =6.63 x 10
-34
Js)     [2] 
 
9. At 273 K the density of a gaseous oxide at 2 bar is the same as that of nitrogen      
(Atomic mass =14u) at 5 bar. Calculate the molar mass of the oxide  [2]        
      
10. Consider the reaction of water with F2 and suggest, in terms of oxidation and       
reduction, which species are oxidized/ reduced.            [2] 
  
  OR 
Complete the following reactions: 
(a) PbS(g) + H2O2(aq)   ?  
(b) CO(g) + 2 H2(g) 
Cobalt
catalyst
? ? ? ?  
 
11. How many neutrons and protons are there in following nuclei?                                   [2] 
            
            (a)
56
26
Fe 
            (b) 
88
38
Sr 
 
12. If density of methanol is 0.793 kg/L, what is its volume needed for making 2.5 L of its 
0.25 M solution?                   [2] 
 
OR 
 
The density of 3 M solution of NaCl is 1.25 g/ml. Calculate the molarity of the solution. 
  
  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
Section C 
 
13. Calculate the energy associated with the first orbit of He
+
. What is the radius of this 
orbit?            [3] 
OR 
An element with mass number 81 contains 3.7% more neutrons as compared to 
protons. Assign the symbol to the element. 
 
14. Element X,Y and Z have 4,5 and 7 valence electrons respectively.    [3] 
(i) Write the molecular formula of the compounds formed by these elements 
individually with hydrogen. 
(ii) Which of these elements will have highest dipole moment?    
          
OR 
 
(a) Which of the two is more stable and why? H2
+
 or H2
-
 
(b) All bonds in PCl5 are not equal. Explain. 
(c) Which of the two is more ionic and why? NaCl or NaI 
 
15. Give reasons:           [3] 
(i) Evaporation causes cooling  
(ii) Falling liquids drops are spherical. 
(iii) Vapour pressure of acetone is less than that of ether at same temperature. 
 
16.                   [3] 
The combustion of one mole of methanol takes place at 298 K and 1 atm. After 
combustion CO2 (g) and H2O(l) are produced and 726 kJ  of heat is liberated. Calculate 
the standard enthalpy of formation of one mole of CH3OH(l). Standard enthalpies of 
formation of CO2(g) and H2O(l) are -393 kJ mol-1 and -286 kJ mol-1 respectively. 
 
17. How many grams of KBr be added to 1 L of 0.05 M solution of silver nitrate just to 
start the precipitation of AgBr?  Ksp of AgBr = 5.0 x 10
-13                        
[3] 
 
OR  
 
Consider the following endothermic reaction:  
      CH 4(g) + H 2O (g)  CO(g) + 3H 2 (g) 
(i) Write expression for K p for the above reaction. 
(ii) How will the equilibrium be affected by  
Increasing the pressure 
Using a catalyst? 
Page 4


  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
CBSE 
CLASS – XI 
CHEMISTRY 
SAMPLE PAPER 3 
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. Arrange the following in the order of decreasing reactivity towards alkenes.   [1] 
 HCl, HBr, HI, HF 
 
2. Predict the shapes of the following molecules using VSEPR theory? 
   BeCl2, SiCl4  [1] 
 
OR 
 
      What is meant by bond pairs of electrons? 
 
3. Give IUPAC name of allyl alcohol. [1] 
 
4. What is biochemical oxygen demand?   [1] 
 
OR 
 
What is the name of the compound formed when CO combines with blood? 
 
 
5. Give the colours shown in the flame test by sodium and potassium.  [1] 
 
  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
Section B 
 
6. How does metallic and nonmetallic character vary on moving from left to right in the 
periodic table? [2] 
     
7. Arrange the following in increasing order of size. Give reason for your answer.   [2] 
            Mg
2+        
O
2-          
Na
+
     F
-
         Al
3+              
.    
   
8. Calculate the wavelength of an electron moving with a velocity of 2.05 x 10
7
m/s.   
 (Mass of electron = 9.1 x 10
-31
kg, h =6.63 x 10
-34
Js)     [2] 
 
9. At 273 K the density of a gaseous oxide at 2 bar is the same as that of nitrogen      
(Atomic mass =14u) at 5 bar. Calculate the molar mass of the oxide  [2]        
      
10. Consider the reaction of water with F2 and suggest, in terms of oxidation and       
reduction, which species are oxidized/ reduced.            [2] 
  
  OR 
Complete the following reactions: 
(a) PbS(g) + H2O2(aq)   ?  
(b) CO(g) + 2 H2(g) 
Cobalt
catalyst
? ? ? ?  
 
11. How many neutrons and protons are there in following nuclei?                                   [2] 
            
            (a)
56
26
Fe 
            (b) 
88
38
Sr 
 
12. If density of methanol is 0.793 kg/L, what is its volume needed for making 2.5 L of its 
0.25 M solution?                   [2] 
 
OR 
 
The density of 3 M solution of NaCl is 1.25 g/ml. Calculate the molarity of the solution. 
  
  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
Section C 
 
13. Calculate the energy associated with the first orbit of He
+
. What is the radius of this 
orbit?            [3] 
OR 
An element with mass number 81 contains 3.7% more neutrons as compared to 
protons. Assign the symbol to the element. 
 
14. Element X,Y and Z have 4,5 and 7 valence electrons respectively.    [3] 
(i) Write the molecular formula of the compounds formed by these elements 
individually with hydrogen. 
(ii) Which of these elements will have highest dipole moment?    
          
OR 
 
(a) Which of the two is more stable and why? H2
+
 or H2
-
 
(b) All bonds in PCl5 are not equal. Explain. 
(c) Which of the two is more ionic and why? NaCl or NaI 
 
15. Give reasons:           [3] 
(i) Evaporation causes cooling  
(ii) Falling liquids drops are spherical. 
(iii) Vapour pressure of acetone is less than that of ether at same temperature. 
 
16.                   [3] 
The combustion of one mole of methanol takes place at 298 K and 1 atm. After 
combustion CO2 (g) and H2O(l) are produced and 726 kJ  of heat is liberated. Calculate 
the standard enthalpy of formation of one mole of CH3OH(l). Standard enthalpies of 
formation of CO2(g) and H2O(l) are -393 kJ mol-1 and -286 kJ mol-1 respectively. 
 
17. How many grams of KBr be added to 1 L of 0.05 M solution of silver nitrate just to 
start the precipitation of AgBr?  Ksp of AgBr = 5.0 x 10
-13                        
[3] 
 
OR  
 
Consider the following endothermic reaction:  
      CH 4(g) + H 2O (g)  CO(g) + 3H 2 (g) 
(i) Write expression for K p for the above reaction. 
(ii) How will the equilibrium be affected by  
Increasing the pressure 
Using a catalyst? 
  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
18. Balance the given redox reaction in acidic medium.     [3] 
MnO4
-
 + SO2 ? Mn
2+
 + HSO4
-
  
   
OR 
 
Balance ? ? ? ?
3 3 4 2 2
P + HNO H PO + NO +H O by oxidation number method.  
           
19.                [3] 
(a) Name the class of hydrides to which H2O and NaH belong. 
(b) What is understood by hydride gap? 
(c) What do you mean by 15 volume H2O2 solution? 
 
20. Write the IUPAC names of the following:                    [3] 
(a)  
       
32
22 55
CH CH CH CH OH
||
C H C H
???
 
 
(b) 
33
CH CH CH l
O
C ? ? ?
 
 
(c)  
                      
21. What are electrophiles? Explain electrophile substitution reaction with the help of 
example           [3] 
 
22. Comment on each of the following observations:     [3] 
(a) Lithium forms a nitride directly like magnesium. Give equation involved. 
(b) BaO is soluble but BaSO4 is insoluble in water. 
 
23.             [3] 
(a) In which C-C bond of CH3CH2CH2Br, the inductive effect is expected to be least?  
(b) What type of isomerism is present in the following pairs? 
(i) CH3CH2COCH2CH3   and CH3COCH2CH2CH3 
(ii) CH3CH2OH and CH3OCH3 
 
Page 5


  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
CBSE 
CLASS – XI 
CHEMISTRY 
SAMPLE PAPER 3 
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. Arrange the following in the order of decreasing reactivity towards alkenes.   [1] 
 HCl, HBr, HI, HF 
 
2. Predict the shapes of the following molecules using VSEPR theory? 
   BeCl2, SiCl4  [1] 
 
OR 
 
      What is meant by bond pairs of electrons? 
 
3. Give IUPAC name of allyl alcohol. [1] 
 
4. What is biochemical oxygen demand?   [1] 
 
OR 
 
What is the name of the compound formed when CO combines with blood? 
 
 
5. Give the colours shown in the flame test by sodium and potassium.  [1] 
 
  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
Section B 
 
6. How does metallic and nonmetallic character vary on moving from left to right in the 
periodic table? [2] 
     
7. Arrange the following in increasing order of size. Give reason for your answer.   [2] 
            Mg
2+        
O
2-          
Na
+
     F
-
         Al
3+              
.    
   
8. Calculate the wavelength of an electron moving with a velocity of 2.05 x 10
7
m/s.   
 (Mass of electron = 9.1 x 10
-31
kg, h =6.63 x 10
-34
Js)     [2] 
 
9. At 273 K the density of a gaseous oxide at 2 bar is the same as that of nitrogen      
(Atomic mass =14u) at 5 bar. Calculate the molar mass of the oxide  [2]        
      
10. Consider the reaction of water with F2 and suggest, in terms of oxidation and       
reduction, which species are oxidized/ reduced.            [2] 
  
  OR 
Complete the following reactions: 
(a) PbS(g) + H2O2(aq)   ?  
(b) CO(g) + 2 H2(g) 
Cobalt
catalyst
? ? ? ?  
 
11. How many neutrons and protons are there in following nuclei?                                   [2] 
            
            (a)
56
26
Fe 
            (b) 
88
38
Sr 
 
12. If density of methanol is 0.793 kg/L, what is its volume needed for making 2.5 L of its 
0.25 M solution?                   [2] 
 
OR 
 
The density of 3 M solution of NaCl is 1.25 g/ml. Calculate the molarity of the solution. 
  
  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
Section C 
 
13. Calculate the energy associated with the first orbit of He
+
. What is the radius of this 
orbit?            [3] 
OR 
An element with mass number 81 contains 3.7% more neutrons as compared to 
protons. Assign the symbol to the element. 
 
14. Element X,Y and Z have 4,5 and 7 valence electrons respectively.    [3] 
(i) Write the molecular formula of the compounds formed by these elements 
individually with hydrogen. 
(ii) Which of these elements will have highest dipole moment?    
          
OR 
 
(a) Which of the two is more stable and why? H2
+
 or H2
-
 
(b) All bonds in PCl5 are not equal. Explain. 
(c) Which of the two is more ionic and why? NaCl or NaI 
 
15. Give reasons:           [3] 
(i) Evaporation causes cooling  
(ii) Falling liquids drops are spherical. 
(iii) Vapour pressure of acetone is less than that of ether at same temperature. 
 
16.                   [3] 
The combustion of one mole of methanol takes place at 298 K and 1 atm. After 
combustion CO2 (g) and H2O(l) are produced and 726 kJ  of heat is liberated. Calculate 
the standard enthalpy of formation of one mole of CH3OH(l). Standard enthalpies of 
formation of CO2(g) and H2O(l) are -393 kJ mol-1 and -286 kJ mol-1 respectively. 
 
17. How many grams of KBr be added to 1 L of 0.05 M solution of silver nitrate just to 
start the precipitation of AgBr?  Ksp of AgBr = 5.0 x 10
-13                        
[3] 
 
OR  
 
Consider the following endothermic reaction:  
      CH 4(g) + H 2O (g)  CO(g) + 3H 2 (g) 
(i) Write expression for K p for the above reaction. 
(ii) How will the equilibrium be affected by  
Increasing the pressure 
Using a catalyst? 
  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
18. Balance the given redox reaction in acidic medium.     [3] 
MnO4
-
 + SO2 ? Mn
2+
 + HSO4
-
  
   
OR 
 
Balance ? ? ? ?
3 3 4 2 2
P + HNO H PO + NO +H O by oxidation number method.  
           
19.                [3] 
(a) Name the class of hydrides to which H2O and NaH belong. 
(b) What is understood by hydride gap? 
(c) What do you mean by 15 volume H2O2 solution? 
 
20. Write the IUPAC names of the following:                    [3] 
(a)  
       
32
22 55
CH CH CH CH OH
||
C H C H
???
 
 
(b) 
33
CH CH CH l
O
C ? ? ?
 
 
(c)  
                      
21. What are electrophiles? Explain electrophile substitution reaction with the help of 
example           [3] 
 
22. Comment on each of the following observations:     [3] 
(a) Lithium forms a nitride directly like magnesium. Give equation involved. 
(b) BaO is soluble but BaSO4 is insoluble in water. 
 
23.             [3] 
(a) In which C-C bond of CH3CH2CH2Br, the inductive effect is expected to be least?  
(b) What type of isomerism is present in the following pairs? 
(i) CH3CH2COCH2CH3   and CH3COCH2CH2CH3 
(ii) CH3CH2OH and CH3OCH3 
 
  
 
CBSE XI | Chemistry 
Sample Paper – 3 
 
    
 
24. Explain:           [3] 
(a) What happens when: 
i. Quicklime is heated with silica 
ii. Calcium nitrate is heated 
(b) When is a cation highly polarising? Which alkali metal ion has the highest 
polarizing power? 
 
 Section D 
 
25. Calculate enthalpy of change for the process: [5] 
           CCl4(g) ? C(g) + 4Cl(g)  
           and calculate bond enthalpy of C-Cl in CCl4 
           Given: ?vapH
-
(CCl4) = 30.5 kJ/mol 
                            ?fH
-
(CCl4) = -135.5 kJ/mol 
 ?aH
-
(C) = 715.0kJ/mol 
 ?aH
-
(Cl2) = 242 kJ/mol 
OR 
 
(a) What is bond energy? Why is it called enthalpy of atomisation? 
(b) Calculate bond energy of C-H bond, given that heat of formation of CH4, heat of 
sublimation of carbon and heat of dissociation of H2 are -74.8, +719.6, 435kJ/mol 
respectively.      
                                                   
26. Explain why?           [5] 
(a) Boric acid is a monobasic lewis acid. 
(b) PbO2 is a stronger oxidizing agent than SnO2. 
(c) CO2 is a gas but SiO2 is solid at room temperature. 
(d) SiF6
2-
 is known but SiCl6
2- 
is not known. 
(e) What is inorganic benzene and why it is so called?  
 
OR 
 
When mental X is treated with sodium hydroxide, a white precipitate (A) is obtained, 
which is soluble in excess of NaOH to give soluble complex (B). Compound (A) is 
soluble in dilute 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. 
27.                           [5] 
(a) Do the following conversions: 
(i) Benzene to p-nitrobromobenzene 
(ii) Ethyl chloride to ethane 
(b) Give mechanism of addition of HBr to propene.