Sample Question Paper 1 - Chemistry, Class 12 | Chemistry for Grade 12 PDF Download

 Page 1


  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
CBSE 
Class XII Chemistry   
Sample Paper - 1 
 
 
Time: 3 Hrs                                                              Total 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 log tables if necessary. Use of a calculator is not allowed.  
 
Section A 
1. A compound contains A atoms at the corners and B atoms at the centres of all faces. What is 
the formula of the compound?           [1] 
OR 
 
        What kind of attractive forces are present in molecular crystalline solids?    
 
2. What are the physical states of the dispersed phase and the dispersion medium of a cloud?     
                    [1]                    
3. Which is the most common oxidation state of lanthanoids?      [1]                    
 
OR 
 
        What is the common oxidation state of Cu, Ag and Au? 
 
4. Give the IUPAC name of the following compound:       [1]                    
           
3 3 2
(CH ) CCH Br 
 
5. Name the monomers of the nylon-2-nylon-6 polymer.      [1]                    
 
Section B 
 
6. State Henry’s law. What is the significance of KH?        [2] 
 
OR 
 
       What would be the value of van’t Hoff factor for a dilute solution of K2SO4 in water? 
 
Page 2


  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
CBSE 
Class XII Chemistry   
Sample Paper - 1 
 
 
Time: 3 Hrs                                                              Total 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 log tables if necessary. Use of a calculator is not allowed.  
 
Section A 
1. A compound contains A atoms at the corners and B atoms at the centres of all faces. What is 
the formula of the compound?           [1] 
OR 
 
        What kind of attractive forces are present in molecular crystalline solids?    
 
2. What are the physical states of the dispersed phase and the dispersion medium of a cloud?     
                    [1]                    
3. Which is the most common oxidation state of lanthanoids?      [1]                    
 
OR 
 
        What is the common oxidation state of Cu, Ag and Au? 
 
4. Give the IUPAC name of the following compound:       [1]                    
           
3 3 2
(CH ) CCH Br 
 
5. Name the monomers of the nylon-2-nylon-6 polymer.      [1]                    
 
Section B 
 
6. State Henry’s law. What is the significance of KH?        [2] 
 
OR 
 
       What would be the value of van’t Hoff factor for a dilute solution of K2SO4 in water? 
 
  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
7. Account for the following:           [2] 
(a) Alkaline medium inhibits the rusting of iron. 
(b) Iron does not rust even if the zinc coating is broken in galvanised iron pipes. 
 
8. Calculate the overall order of a reaction which has the rate expression   [2] 
(a) Rate = k[A]
1/2
 [B]
3/2
 
(b) Rate = k [A]
3/2
 [B]
-1
 
 
9. Complete the following chemical reaction equations:           [2] 
(a) XeF2 + H2O ? 
(b) PH3 + HgCl2? 
 
10.  What happens when                      [2]                                                                                                   
(a) Phenol reacts with Br2 in CS2 at 273 K. 
(b) Phenol reacts with conc. HNO3.  
 
11. Out of acetophenone and benzophenone, which gives the iodoform test? Write the reactions 
involved.             [2] 
OR 
 
       Draw the structures of the following compounds: 
(a) 3-methyl butanal 
(b) 4-chloropentan-2-one 
 
12. Write the structure of the monomers of the following polymers:     [2] 
(a) PVC 
(b) Polypropene 
 
Section C 
 
13. Chromium crystallises in BCC structure. If its atomic diameter is 245 pm, find its density. 
Atomic mass of Cr = 52 amu and NA = 6.02 × 10
23
 mol
-1
.          [3] 
 
 
14. A solution is made by dissolving 30 g of a non-volatile solute in 90 g of water. It has a vapour 
pressure of 2.8 kPa at 298 K. The vapour pressure of pure water is 3.64 kPa. Calculate the 
molar mass of the solute.          [3] 
OR 
 
       Calculate the freezing point of depression expected for 0.0711 m aqueous solution of 
Na2SO4. If this solution actually freezes at -0.320 ?C, then what would be the value of van’t 
Hoff factor? (Kf = 1.86 ?C) 
 
15. The decomposition of Cl2O7 at 400 K in the gas phase to Cl2 and O2 is a first-order reaction.  
[3] 
(a) After 55 s at 400 K, the pressure of Cl2O7 falls from 0.062 to 0.044 atm. Calculate the rate 
constant. 
(b) Calculate the pressure of Cl2O7 after 100 s of decomposition at this temperature. 
Page 3


  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
CBSE 
Class XII Chemistry   
Sample Paper - 1 
 
 
Time: 3 Hrs                                                              Total 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 log tables if necessary. Use of a calculator is not allowed.  
 
Section A 
1. A compound contains A atoms at the corners and B atoms at the centres of all faces. What is 
the formula of the compound?           [1] 
OR 
 
        What kind of attractive forces are present in molecular crystalline solids?    
 
2. What are the physical states of the dispersed phase and the dispersion medium of a cloud?     
                    [1]                    
3. Which is the most common oxidation state of lanthanoids?      [1]                    
 
OR 
 
        What is the common oxidation state of Cu, Ag and Au? 
 
4. Give the IUPAC name of the following compound:       [1]                    
           
3 3 2
(CH ) CCH Br 
 
5. Name the monomers of the nylon-2-nylon-6 polymer.      [1]                    
 
Section B 
 
6. State Henry’s law. What is the significance of KH?        [2] 
 
OR 
 
       What would be the value of van’t Hoff factor for a dilute solution of K2SO4 in water? 
 
  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
7. Account for the following:           [2] 
(a) Alkaline medium inhibits the rusting of iron. 
(b) Iron does not rust even if the zinc coating is broken in galvanised iron pipes. 
 
8. Calculate the overall order of a reaction which has the rate expression   [2] 
(a) Rate = k[A]
1/2
 [B]
3/2
 
(b) Rate = k [A]
3/2
 [B]
-1
 
 
9. Complete the following chemical reaction equations:           [2] 
(a) XeF2 + H2O ? 
(b) PH3 + HgCl2? 
 
10.  What happens when                      [2]                                                                                                   
(a) Phenol reacts with Br2 in CS2 at 273 K. 
(b) Phenol reacts with conc. HNO3.  
 
11. Out of acetophenone and benzophenone, which gives the iodoform test? Write the reactions 
involved.             [2] 
OR 
 
       Draw the structures of the following compounds: 
(a) 3-methyl butanal 
(b) 4-chloropentan-2-one 
 
12. Write the structure of the monomers of the following polymers:     [2] 
(a) PVC 
(b) Polypropene 
 
Section C 
 
13. Chromium crystallises in BCC structure. If its atomic diameter is 245 pm, find its density. 
Atomic mass of Cr = 52 amu and NA = 6.02 × 10
23
 mol
-1
.          [3] 
 
 
14. A solution is made by dissolving 30 g of a non-volatile solute in 90 g of water. It has a vapour 
pressure of 2.8 kPa at 298 K. The vapour pressure of pure water is 3.64 kPa. Calculate the 
molar mass of the solute.          [3] 
OR 
 
       Calculate the freezing point of depression expected for 0.0711 m aqueous solution of 
Na2SO4. If this solution actually freezes at -0.320 ?C, then what would be the value of van’t 
Hoff factor? (Kf = 1.86 ?C) 
 
15. The decomposition of Cl2O7 at 400 K in the gas phase to Cl2 and O2 is a first-order reaction.  
[3] 
(a) After 55 s at 400 K, the pressure of Cl2O7 falls from 0.062 to 0.044 atm. Calculate the rate 
constant. 
(b) Calculate the pressure of Cl2O7 after 100 s of decomposition at this temperature. 
  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
16.                                 [3] 
(a) Why are deltas formed at places where the river meets the sea? 
(b) List two characteristics of catalysts. 
(c) What are macromolecular colloids? Give an example. 
 
17. State briefly the principles which serve as the basis for the following operations in 
metallurgy:            [3] 
(a) Froth flotation process 
(b) Zone refining 
(c) Refining by liquation 
 
18. Complete the following chemical equations:        [3] 
(a) 
2
4 2 4
MnO C O H
? ? ?
? ? ? ? ? 
(b) 
Heat
4
KMnO ? ? ? 
(c) 
2
2 7 2
Cr O H S H
??
? ? ? ? ? 
 
19.                               [3] 
(a) Give the IUPAC name of K3[Cr(C2O4)3]. 
(b) What is the number of unpaired electrons in [CoF6]
3- 
 and [Co(NH3)6]
3+
?       
(c) Name the isomerism exhibited by the following pair of compounds: 
[Co(en)2(H2O)Cl]Cl2 and [Co(en)2Cl2]Cl.H2O] 
 
20. Answer the following questions:          [3] 
(a) What is meant by chirality of a compound? Give an example. 
(b) Which of the following compounds is more easily hydrolysed by KOH and why? 
          
3 2 3 3 2 2
CH CHClCH CH or CH CH CH Cl 
(c) Which one undergoes SN2 substitution reaction faster and why? 
                        
 
OR 
 
(a) Give a chemical test to distinguish between chlorobenzene and benzyl chloride. 
(b) Identify A, B, C and D: 
 
Page 4


  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
CBSE 
Class XII Chemistry   
Sample Paper - 1 
 
 
Time: 3 Hrs                                                              Total 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 log tables if necessary. Use of a calculator is not allowed.  
 
Section A 
1. A compound contains A atoms at the corners and B atoms at the centres of all faces. What is 
the formula of the compound?           [1] 
OR 
 
        What kind of attractive forces are present in molecular crystalline solids?    
 
2. What are the physical states of the dispersed phase and the dispersion medium of a cloud?     
                    [1]                    
3. Which is the most common oxidation state of lanthanoids?      [1]                    
 
OR 
 
        What is the common oxidation state of Cu, Ag and Au? 
 
4. Give the IUPAC name of the following compound:       [1]                    
           
3 3 2
(CH ) CCH Br 
 
5. Name the monomers of the nylon-2-nylon-6 polymer.      [1]                    
 
Section B 
 
6. State Henry’s law. What is the significance of KH?        [2] 
 
OR 
 
       What would be the value of van’t Hoff factor for a dilute solution of K2SO4 in water? 
 
  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
7. Account for the following:           [2] 
(a) Alkaline medium inhibits the rusting of iron. 
(b) Iron does not rust even if the zinc coating is broken in galvanised iron pipes. 
 
8. Calculate the overall order of a reaction which has the rate expression   [2] 
(a) Rate = k[A]
1/2
 [B]
3/2
 
(b) Rate = k [A]
3/2
 [B]
-1
 
 
9. Complete the following chemical reaction equations:           [2] 
(a) XeF2 + H2O ? 
(b) PH3 + HgCl2? 
 
10.  What happens when                      [2]                                                                                                   
(a) Phenol reacts with Br2 in CS2 at 273 K. 
(b) Phenol reacts with conc. HNO3.  
 
11. Out of acetophenone and benzophenone, which gives the iodoform test? Write the reactions 
involved.             [2] 
OR 
 
       Draw the structures of the following compounds: 
(a) 3-methyl butanal 
(b) 4-chloropentan-2-one 
 
12. Write the structure of the monomers of the following polymers:     [2] 
(a) PVC 
(b) Polypropene 
 
Section C 
 
13. Chromium crystallises in BCC structure. If its atomic diameter is 245 pm, find its density. 
Atomic mass of Cr = 52 amu and NA = 6.02 × 10
23
 mol
-1
.          [3] 
 
 
14. A solution is made by dissolving 30 g of a non-volatile solute in 90 g of water. It has a vapour 
pressure of 2.8 kPa at 298 K. The vapour pressure of pure water is 3.64 kPa. Calculate the 
molar mass of the solute.          [3] 
OR 
 
       Calculate the freezing point of depression expected for 0.0711 m aqueous solution of 
Na2SO4. If this solution actually freezes at -0.320 ?C, then what would be the value of van’t 
Hoff factor? (Kf = 1.86 ?C) 
 
15. The decomposition of Cl2O7 at 400 K in the gas phase to Cl2 and O2 is a first-order reaction.  
[3] 
(a) After 55 s at 400 K, the pressure of Cl2O7 falls from 0.062 to 0.044 atm. Calculate the rate 
constant. 
(b) Calculate the pressure of Cl2O7 after 100 s of decomposition at this temperature. 
  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
16.                                 [3] 
(a) Why are deltas formed at places where the river meets the sea? 
(b) List two characteristics of catalysts. 
(c) What are macromolecular colloids? Give an example. 
 
17. State briefly the principles which serve as the basis for the following operations in 
metallurgy:            [3] 
(a) Froth flotation process 
(b) Zone refining 
(c) Refining by liquation 
 
18. Complete the following chemical equations:        [3] 
(a) 
2
4 2 4
MnO C O H
? ? ?
? ? ? ? ? 
(b) 
Heat
4
KMnO ? ? ? 
(c) 
2
2 7 2
Cr O H S H
??
? ? ? ? ? 
 
19.                               [3] 
(a) Give the IUPAC name of K3[Cr(C2O4)3]. 
(b) What is the number of unpaired electrons in [CoF6]
3- 
 and [Co(NH3)6]
3+
?       
(c) Name the isomerism exhibited by the following pair of compounds: 
[Co(en)2(H2O)Cl]Cl2 and [Co(en)2Cl2]Cl.H2O] 
 
20. Answer the following questions:          [3] 
(a) What is meant by chirality of a compound? Give an example. 
(b) Which of the following compounds is more easily hydrolysed by KOH and why? 
          
3 2 3 3 2 2
CH CHClCH CH or CH CH CH Cl 
(c) Which one undergoes SN2 substitution reaction faster and why? 
                        
 
OR 
 
(a) Give a chemical test to distinguish between chlorobenzene and benzyl chloride. 
(b) Identify A, B, C and D: 
 
  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
21. Give the equation of the following reactions:        [3] 
(a) Oxidation of propan-1-ol with alkaline KMnO4 solution. 
(b) Bromine in CS2 with phenol. 
(c) Dilute nitric acid with phenol. 
 
22. In the following cases, rearrange the compounds as directed:     [3] 
(a) In the increasing order of basic strength: 
           C6H5NH2, C6H5N(CH3)2, (C2H5)2NH and CH3NH2 
 
(b) In the decreasing order of basic strength: 
           Aniline, p-nitroaniline and p-toluidine 
 
(c) In the increasing order of pKb value: 
           C2H5NH2, C6H5NHCH3, (C2H5)2NH and C6H5NH2 
 
23. Name three fat-soluble vitamins, their source and the diseases caused by their deficiency in 
the diet.                    [3] 
 
OR 
 
Explain the following terms: 
(a) Peptide linkage 
(b) Pyranose structure of glucose 
(c) Glycosidic linkage 
 
24. Give reason for the following:          [3] 
(a) Sulpha drugs work like antibiotics, but they are not antibiotics. 
(b) Aspirin helps in the prevention of heart attack. 
(c) Soaps are biodegradable, whereas detergents are non-biodegradable. 
 
Section D 
25.                              [5] 
(a) Name two transition elements which show +1 oxidation state. 
(b) Name the transition element which does not exhibit variable oxidation state. 
(c) Transition elements show catalytic properties. Why? 
(d) Explain why Cu
+
 ion is not stable in aqueous solutions. 
 
OR 
 
(a) Write the steps involved in the preparation of                                                      
(i) Na2CrO4 from chromite ore 
(ii) K2MnO4 from pyrolusite ore 
(b) What is the effect of increasing pH on K2Cr2O7 solution? 
(c) Draw the structure of dichromate ion indicating the bond angles and bond lengths. 
 
 
 
Page 5


  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
CBSE 
Class XII Chemistry   
Sample Paper - 1 
 
 
Time: 3 Hrs                                                              Total 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 log tables if necessary. Use of a calculator is not allowed.  
 
Section A 
1. A compound contains A atoms at the corners and B atoms at the centres of all faces. What is 
the formula of the compound?           [1] 
OR 
 
        What kind of attractive forces are present in molecular crystalline solids?    
 
2. What are the physical states of the dispersed phase and the dispersion medium of a cloud?     
                    [1]                    
3. Which is the most common oxidation state of lanthanoids?      [1]                    
 
OR 
 
        What is the common oxidation state of Cu, Ag and Au? 
 
4. Give the IUPAC name of the following compound:       [1]                    
           
3 3 2
(CH ) CCH Br 
 
5. Name the monomers of the nylon-2-nylon-6 polymer.      [1]                    
 
Section B 
 
6. State Henry’s law. What is the significance of KH?        [2] 
 
OR 
 
       What would be the value of van’t Hoff factor for a dilute solution of K2SO4 in water? 
 
  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
7. Account for the following:           [2] 
(a) Alkaline medium inhibits the rusting of iron. 
(b) Iron does not rust even if the zinc coating is broken in galvanised iron pipes. 
 
8. Calculate the overall order of a reaction which has the rate expression   [2] 
(a) Rate = k[A]
1/2
 [B]
3/2
 
(b) Rate = k [A]
3/2
 [B]
-1
 
 
9. Complete the following chemical reaction equations:           [2] 
(a) XeF2 + H2O ? 
(b) PH3 + HgCl2? 
 
10.  What happens when                      [2]                                                                                                   
(a) Phenol reacts with Br2 in CS2 at 273 K. 
(b) Phenol reacts with conc. HNO3.  
 
11. Out of acetophenone and benzophenone, which gives the iodoform test? Write the reactions 
involved.             [2] 
OR 
 
       Draw the structures of the following compounds: 
(a) 3-methyl butanal 
(b) 4-chloropentan-2-one 
 
12. Write the structure of the monomers of the following polymers:     [2] 
(a) PVC 
(b) Polypropene 
 
Section C 
 
13. Chromium crystallises in BCC structure. If its atomic diameter is 245 pm, find its density. 
Atomic mass of Cr = 52 amu and NA = 6.02 × 10
23
 mol
-1
.          [3] 
 
 
14. A solution is made by dissolving 30 g of a non-volatile solute in 90 g of water. It has a vapour 
pressure of 2.8 kPa at 298 K. The vapour pressure of pure water is 3.64 kPa. Calculate the 
molar mass of the solute.          [3] 
OR 
 
       Calculate the freezing point of depression expected for 0.0711 m aqueous solution of 
Na2SO4. If this solution actually freezes at -0.320 ?C, then what would be the value of van’t 
Hoff factor? (Kf = 1.86 ?C) 
 
15. The decomposition of Cl2O7 at 400 K in the gas phase to Cl2 and O2 is a first-order reaction.  
[3] 
(a) After 55 s at 400 K, the pressure of Cl2O7 falls from 0.062 to 0.044 atm. Calculate the rate 
constant. 
(b) Calculate the pressure of Cl2O7 after 100 s of decomposition at this temperature. 
  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
16.                                 [3] 
(a) Why are deltas formed at places where the river meets the sea? 
(b) List two characteristics of catalysts. 
(c) What are macromolecular colloids? Give an example. 
 
17. State briefly the principles which serve as the basis for the following operations in 
metallurgy:            [3] 
(a) Froth flotation process 
(b) Zone refining 
(c) Refining by liquation 
 
18. Complete the following chemical equations:        [3] 
(a) 
2
4 2 4
MnO C O H
? ? ?
? ? ? ? ? 
(b) 
Heat
4
KMnO ? ? ? 
(c) 
2
2 7 2
Cr O H S H
??
? ? ? ? ? 
 
19.                               [3] 
(a) Give the IUPAC name of K3[Cr(C2O4)3]. 
(b) What is the number of unpaired electrons in [CoF6]
3- 
 and [Co(NH3)6]
3+
?       
(c) Name the isomerism exhibited by the following pair of compounds: 
[Co(en)2(H2O)Cl]Cl2 and [Co(en)2Cl2]Cl.H2O] 
 
20. Answer the following questions:          [3] 
(a) What is meant by chirality of a compound? Give an example. 
(b) Which of the following compounds is more easily hydrolysed by KOH and why? 
          
3 2 3 3 2 2
CH CHClCH CH or CH CH CH Cl 
(c) Which one undergoes SN2 substitution reaction faster and why? 
                        
 
OR 
 
(a) Give a chemical test to distinguish between chlorobenzene and benzyl chloride. 
(b) Identify A, B, C and D: 
 
  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
21. Give the equation of the following reactions:        [3] 
(a) Oxidation of propan-1-ol with alkaline KMnO4 solution. 
(b) Bromine in CS2 with phenol. 
(c) Dilute nitric acid with phenol. 
 
22. In the following cases, rearrange the compounds as directed:     [3] 
(a) In the increasing order of basic strength: 
           C6H5NH2, C6H5N(CH3)2, (C2H5)2NH and CH3NH2 
 
(b) In the decreasing order of basic strength: 
           Aniline, p-nitroaniline and p-toluidine 
 
(c) In the increasing order of pKb value: 
           C2H5NH2, C6H5NHCH3, (C2H5)2NH and C6H5NH2 
 
23. Name three fat-soluble vitamins, their source and the diseases caused by their deficiency in 
the diet.                    [3] 
 
OR 
 
Explain the following terms: 
(a) Peptide linkage 
(b) Pyranose structure of glucose 
(c) Glycosidic linkage 
 
24. Give reason for the following:          [3] 
(a) Sulpha drugs work like antibiotics, but they are not antibiotics. 
(b) Aspirin helps in the prevention of heart attack. 
(c) Soaps are biodegradable, whereas detergents are non-biodegradable. 
 
Section D 
25.                              [5] 
(a) Name two transition elements which show +1 oxidation state. 
(b) Name the transition element which does not exhibit variable oxidation state. 
(c) Transition elements show catalytic properties. Why? 
(d) Explain why Cu
+
 ion is not stable in aqueous solutions. 
 
OR 
 
(a) Write the steps involved in the preparation of                                                      
(i) Na2CrO4 from chromite ore 
(ii) K2MnO4 from pyrolusite ore 
(b) What is the effect of increasing pH on K2Cr2O7 solution? 
(c) Draw the structure of dichromate ion indicating the bond angles and bond lengths. 
 
 
 
  
 
CBSE XII  |  Chemistry  
Sample Paper 1 
 
     
26. The emf of the cell reaction          [5] 
          3Sn
4+
 + 2 Cr ? 3Sn
2+
 + 2Cr
3+
 is 0.89 V.  
         Calculate: 
(a)  for the reaction. 
(b) Equilibrium constant for the reaction relating to 
(i)   
(ii) cell                     
 
OR 
Given: 
Cu
2+
 + 2e
-
 ? Cu  E
? 
= +0.34 V 
Ag
+
 + e
-
 ? Ag  E
? 
= +0.80 V 
(a) Write the cell reaction. 
(b) Construct the galvanic cell. 
(c) For what concentration of Ag+ ions will the emf of the cell be zero at 25°C if the 
concentration of Cu
2+
 is 0.01 M?       
                                                                           
27.                                                          [5] 
(a) Ethanol reacts with acetic acid in the presence of conc. H2SO4 to give a sweet smelling 
substance. Give the equation involved in the reaction.  
(b) Write a note on  
(i)  Rosenmund’s reduction                                          
(ii) Hell Volhard Zelinsky reaction                                                                                                                                        
                               
OR 
 
(a)   Complete the equations: 
(i) 
3 2
NH Br /KOH
32
CH CH COOH A B ? ? ? ? ? ?? ? ?
 
(ii) 
2
H /Ni HCN
3
(CH )C=O X Y ? ? ? ? ? ?? ?
 
(iii) 
-
dil OH
6 5 3 3
C H CHO+CH COCH C + D ? ?? ?
 
 
(b) Semicarbazide contains two NH2 groups, but only one participates in the reaction with   
carbonyl compounds. Why? 
 
(c) Which of the two will give a yellow precipitate with iodine and sodium hydroxide: 
pentan-2-one or pentan-3-one?                                                                        
 
?
G ?
?
G ?
?
E