Chemistry: Sample Question Paper- 2, Class 12 Notes | EduRev

 Page 1


  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
 
CBSE 
Class XII Chemistry   
Sample Paper 2 
 
 
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. Alcohols have a higher boiling point compared to isomeric ethers. Why?                 [1] 
 
2. Define: Polymerisation          [1] 
 
3. What is the number of atoms in a unit cell of a cubic crystal?     [1] 
OR 
 
       What type of crystal defect is produced when sodium chloride is doped with MgCl2? 
 
4. Give one example each of ‘oil in water’ and ‘water in oil’ emulsion.           [1] 
 
5. Calculate the magnetic moment of a divalent ion in aqueous solution if its atomic number is 
25.                          [1] 
OR 
 
Arrange the following radicals in increasing order of their oxidising power: 
7
2
4 2 2
MnO , VO , Cr O
? ? ?
 
Section B 
6. A solution prepared by dissolving 1.25 g of methyl salicylate in 99.0 g of benzene has a 
boiling point of 80.31 ?C. Determine the molar mass of this compound.    [2] 
(BP of pure benzene = 80.10 ?C and Kb for benzene = 2.53 ?C kg mol
-1
) 
 
OR 
 
Calculate the freezing point of an aqueous solution containing 10.50 g of MgBr2 in 200 g of 
water. (Molar mass of MgBr2 = 84 g) (Kf  for water = 1.86 K  kg mol
-1
) 
Page 2


  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
 
CBSE 
Class XII Chemistry   
Sample Paper 2 
 
 
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. Alcohols have a higher boiling point compared to isomeric ethers. Why?                 [1] 
 
2. Define: Polymerisation          [1] 
 
3. What is the number of atoms in a unit cell of a cubic crystal?     [1] 
OR 
 
       What type of crystal defect is produced when sodium chloride is doped with MgCl2? 
 
4. Give one example each of ‘oil in water’ and ‘water in oil’ emulsion.           [1] 
 
5. Calculate the magnetic moment of a divalent ion in aqueous solution if its atomic number is 
25.                          [1] 
OR 
 
Arrange the following radicals in increasing order of their oxidising power: 
7
2
4 2 2
MnO , VO , Cr O
? ? ?
 
Section B 
6. A solution prepared by dissolving 1.25 g of methyl salicylate in 99.0 g of benzene has a 
boiling point of 80.31 ?C. Determine the molar mass of this compound.    [2] 
(BP of pure benzene = 80.10 ?C and Kb for benzene = 2.53 ?C kg mol
-1
) 
 
OR 
 
Calculate the freezing point of an aqueous solution containing 10.50 g of MgBr2 in 200 g of 
water. (Molar mass of MgBr2 = 84 g) (Kf  for water = 1.86 K  kg mol
-1
) 
  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
7. Give the resonating structures of NO2 and N2O5.       [2] 
 
8. How is acetone obtained from ethanol?                 [2] 
 
9. Write the electrode reactions taking place in the Ni–Cd cell.      [2] 
 
10. For reaction: A + H2O ? B, Rate a [A], what is its           [2] 
(a) Molecularity 
(b) Order of reaction 
 
 
11. Give a chemical test to distinguish between the following pairs of compounds.          [2] 
(a)  
 
 
(b)  
 
 
12. Classify the following as addition and condensation polymers:     [2] 
terylene, Bakelite, polyvinyl chloride, polyethene 
 
 
Section C 
 
13. Draw the structures of isomers, if any, and write the names of the following complexes:   [3] 
(a) [Cr(NH3)4Cl2]
+
 
(b) [Co(en)3]
3+
 
(c) [CoCl2(en)2]Cl 
     
14. Examine the illustration of a portion of the defective crystal and answer the following 
questions:                                                                                                                                                      [3]                                                                                           
                  
                                                   
(a) What are these types of valency defects called? 
(b) How is the density of a crystal affected by these defects? 
(c) Name one ionic compound which can show this type of 
defect in the crystalline state. 
                                                                                                                                             
Page 3


  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
 
CBSE 
Class XII Chemistry   
Sample Paper 2 
 
 
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. Alcohols have a higher boiling point compared to isomeric ethers. Why?                 [1] 
 
2. Define: Polymerisation          [1] 
 
3. What is the number of atoms in a unit cell of a cubic crystal?     [1] 
OR 
 
       What type of crystal defect is produced when sodium chloride is doped with MgCl2? 
 
4. Give one example each of ‘oil in water’ and ‘water in oil’ emulsion.           [1] 
 
5. Calculate the magnetic moment of a divalent ion in aqueous solution if its atomic number is 
25.                          [1] 
OR 
 
Arrange the following radicals in increasing order of their oxidising power: 
7
2
4 2 2
MnO , VO , Cr O
? ? ?
 
Section B 
6. A solution prepared by dissolving 1.25 g of methyl salicylate in 99.0 g of benzene has a 
boiling point of 80.31 ?C. Determine the molar mass of this compound.    [2] 
(BP of pure benzene = 80.10 ?C and Kb for benzene = 2.53 ?C kg mol
-1
) 
 
OR 
 
Calculate the freezing point of an aqueous solution containing 10.50 g of MgBr2 in 200 g of 
water. (Molar mass of MgBr2 = 84 g) (Kf  for water = 1.86 K  kg mol
-1
) 
  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
7. Give the resonating structures of NO2 and N2O5.       [2] 
 
8. How is acetone obtained from ethanol?                 [2] 
 
9. Write the electrode reactions taking place in the Ni–Cd cell.      [2] 
 
10. For reaction: A + H2O ? B, Rate a [A], what is its           [2] 
(a) Molecularity 
(b) Order of reaction 
 
 
11. Give a chemical test to distinguish between the following pairs of compounds.          [2] 
(a)  
 
 
(b)  
 
 
12. Classify the following as addition and condensation polymers:     [2] 
terylene, Bakelite, polyvinyl chloride, polyethene 
 
 
Section C 
 
13. Draw the structures of isomers, if any, and write the names of the following complexes:   [3] 
(a) [Cr(NH3)4Cl2]
+
 
(b) [Co(en)3]
3+
 
(c) [CoCl2(en)2]Cl 
     
14. Examine the illustration of a portion of the defective crystal and answer the following 
questions:                                                                                                                                                      [3]                                                                                           
                  
                                                   
(a) What are these types of valency defects called? 
(b) How is the density of a crystal affected by these defects? 
(c) Name one ionic compound which can show this type of 
defect in the crystalline state. 
                                                                                                                                             
  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
15. What method would you suggest for the separation of metals in the following mixtures? [3] 
(a) Zinc and iron 
(b) Copper and magnesium 
(c) Rare earth 
OR 
 
Write the reactions taking place in the different zones in the blast furnace during the 
extraction of iron. 
 
16. 18 g of glucose, C6H12O6, is dissolved in 1 kg of water in a saucepan. At what temperature 
will water boil at 1.013 bar? (Kb for water is 0.52 K kg mol
-1
.)     [3] 
 
OR 
 
Why is the boiling point of a solution containing a non-volatile solute more than that of pure 
solvent? Explain graphically. 
 
17.                                         [3] 
(a) Give the mechanism of acid-catalysed dehydration of ethanol to yield ethyne. 
(b) Compound (A) C4H10O is found to be soluble in sulphuric acid. (A) does not react with 
sodium metal or potassium permanganate. When it is heated with excess of HI, it is 
converted to a single alkyl halide. What is the structural formula of (A)? 
 
18. It is observed that the rate of a chemical reaction doubles with every 10
°
 rise in 
temperature. If this generalisation holds good for a reaction in the temperature range 295–
305 K, what would be the volume of activation energy for this reaction?              [3] 
(R = 8.314 J/Kmol) 
 
19.                                                         [3] 
(a) Give two reasons to support the cyclic structure of glucose. 
(b) Why are amino acids soluble in water? 
(c) Name the pyrimidine bases present in DNA and RNA. 
 
 
20. Explain the following observations:         [3] 
(a) Lyophilic colloid is more stable than lyophobic colloid. 
(b) Coagulation takes place when sodium chloride solution is added to a colloidal solution of 
ferric hydroxide. 
(c) The sky appears blue in colour. 
 
 
21.                                                [3] 
(a) Distinguish between 
(i) Aniline and benzyl amine                                   
(ii) CH3CH2NH2 and (CH3)2NH                              
(b) Write a note on the Hoffmann bromamide reaction.  
 
Page 4


  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
 
CBSE 
Class XII Chemistry   
Sample Paper 2 
 
 
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. Alcohols have a higher boiling point compared to isomeric ethers. Why?                 [1] 
 
2. Define: Polymerisation          [1] 
 
3. What is the number of atoms in a unit cell of a cubic crystal?     [1] 
OR 
 
       What type of crystal defect is produced when sodium chloride is doped with MgCl2? 
 
4. Give one example each of ‘oil in water’ and ‘water in oil’ emulsion.           [1] 
 
5. Calculate the magnetic moment of a divalent ion in aqueous solution if its atomic number is 
25.                          [1] 
OR 
 
Arrange the following radicals in increasing order of their oxidising power: 
7
2
4 2 2
MnO , VO , Cr O
? ? ?
 
Section B 
6. A solution prepared by dissolving 1.25 g of methyl salicylate in 99.0 g of benzene has a 
boiling point of 80.31 ?C. Determine the molar mass of this compound.    [2] 
(BP of pure benzene = 80.10 ?C and Kb for benzene = 2.53 ?C kg mol
-1
) 
 
OR 
 
Calculate the freezing point of an aqueous solution containing 10.50 g of MgBr2 in 200 g of 
water. (Molar mass of MgBr2 = 84 g) (Kf  for water = 1.86 K  kg mol
-1
) 
  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
7. Give the resonating structures of NO2 and N2O5.       [2] 
 
8. How is acetone obtained from ethanol?                 [2] 
 
9. Write the electrode reactions taking place in the Ni–Cd cell.      [2] 
 
10. For reaction: A + H2O ? B, Rate a [A], what is its           [2] 
(a) Molecularity 
(b) Order of reaction 
 
 
11. Give a chemical test to distinguish between the following pairs of compounds.          [2] 
(a)  
 
 
(b)  
 
 
12. Classify the following as addition and condensation polymers:     [2] 
terylene, Bakelite, polyvinyl chloride, polyethene 
 
 
Section C 
 
13. Draw the structures of isomers, if any, and write the names of the following complexes:   [3] 
(a) [Cr(NH3)4Cl2]
+
 
(b) [Co(en)3]
3+
 
(c) [CoCl2(en)2]Cl 
     
14. Examine the illustration of a portion of the defective crystal and answer the following 
questions:                                                                                                                                                      [3]                                                                                           
                  
                                                   
(a) What are these types of valency defects called? 
(b) How is the density of a crystal affected by these defects? 
(c) Name one ionic compound which can show this type of 
defect in the crystalline state. 
                                                                                                                                             
  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
15. What method would you suggest for the separation of metals in the following mixtures? [3] 
(a) Zinc and iron 
(b) Copper and magnesium 
(c) Rare earth 
OR 
 
Write the reactions taking place in the different zones in the blast furnace during the 
extraction of iron. 
 
16. 18 g of glucose, C6H12O6, is dissolved in 1 kg of water in a saucepan. At what temperature 
will water boil at 1.013 bar? (Kb for water is 0.52 K kg mol
-1
.)     [3] 
 
OR 
 
Why is the boiling point of a solution containing a non-volatile solute more than that of pure 
solvent? Explain graphically. 
 
17.                                         [3] 
(a) Give the mechanism of acid-catalysed dehydration of ethanol to yield ethyne. 
(b) Compound (A) C4H10O is found to be soluble in sulphuric acid. (A) does not react with 
sodium metal or potassium permanganate. When it is heated with excess of HI, it is 
converted to a single alkyl halide. What is the structural formula of (A)? 
 
18. It is observed that the rate of a chemical reaction doubles with every 10
°
 rise in 
temperature. If this generalisation holds good for a reaction in the temperature range 295–
305 K, what would be the volume of activation energy for this reaction?              [3] 
(R = 8.314 J/Kmol) 
 
19.                                                         [3] 
(a) Give two reasons to support the cyclic structure of glucose. 
(b) Why are amino acids soluble in water? 
(c) Name the pyrimidine bases present in DNA and RNA. 
 
 
20. Explain the following observations:         [3] 
(a) Lyophilic colloid is more stable than lyophobic colloid. 
(b) Coagulation takes place when sodium chloride solution is added to a colloidal solution of 
ferric hydroxide. 
(c) The sky appears blue in colour. 
 
 
21.                                                [3] 
(a) Distinguish between 
(i) Aniline and benzyl amine                                   
(ii) CH3CH2NH2 and (CH3)2NH                              
(b) Write a note on the Hoffmann bromamide reaction.  
 
  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
22.                                     [3] 
(a) Why do transition metals form complex compounds?                                             
(b) What is lanthanoid contraction? 
(c) Why does Cr have a high melting point? 
 
 
23. Arrange the following in order of increasing reactivity in SN1 and SN2 reactions:   [3] 
C6H5CH2Br, C6H5CH (C6H5) Br, C6H5CH (CH3) Br, C6H5C (CH3) (C6H5) Br  
  
OR 
  
        What happens when                                                                                                     
(a) Chloroethane is made to react with KCN. 
(b) 1-Bromopropane reacts with silver acetate.  
             Give equations involved. 
 
24. What are antihistamines? Give an example. Discuss their working in the human body. [3] 
 
OR 
            
Account for the following: 
(a) Aspirin drug helps in the prevention of heart attack. 
(b) Diabetic patients are advised to take artificial sweeteners instead of natural 
sweeteners.  
(c)  Detergents are non-biodegradable, while soaps are biodegradable. 
 
 
Section D 
 
25.   Complete the equations:          [5]                                                                                               
(a) NaCl + MnO2 + H2SO4  
(b) Al + O2  
(c)  
(d) C + H 2SO4 (conc.)   
(e) PbS + O3  
OR 
           
Complete the equations: 
(a) NH4Cl(aq)  + NaNO2(aq)  
(b) P4  +  NaOH  +  H2O  
(c) CaF2  + H2SO4   
(d) NaOH (conc. hot)  + Cl2   
(e) PCl3  +  H2O   
 
 
?
?
? ? ? ? ?
673 K
32
2Pb(NO )   
?
?
?
?
?
?
?
Page 5


  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
 
CBSE 
Class XII Chemistry   
Sample Paper 2 
 
 
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. Alcohols have a higher boiling point compared to isomeric ethers. Why?                 [1] 
 
2. Define: Polymerisation          [1] 
 
3. What is the number of atoms in a unit cell of a cubic crystal?     [1] 
OR 
 
       What type of crystal defect is produced when sodium chloride is doped with MgCl2? 
 
4. Give one example each of ‘oil in water’ and ‘water in oil’ emulsion.           [1] 
 
5. Calculate the magnetic moment of a divalent ion in aqueous solution if its atomic number is 
25.                          [1] 
OR 
 
Arrange the following radicals in increasing order of their oxidising power: 
7
2
4 2 2
MnO , VO , Cr O
? ? ?
 
Section B 
6. A solution prepared by dissolving 1.25 g of methyl salicylate in 99.0 g of benzene has a 
boiling point of 80.31 ?C. Determine the molar mass of this compound.    [2] 
(BP of pure benzene = 80.10 ?C and Kb for benzene = 2.53 ?C kg mol
-1
) 
 
OR 
 
Calculate the freezing point of an aqueous solution containing 10.50 g of MgBr2 in 200 g of 
water. (Molar mass of MgBr2 = 84 g) (Kf  for water = 1.86 K  kg mol
-1
) 
  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
7. Give the resonating structures of NO2 and N2O5.       [2] 
 
8. How is acetone obtained from ethanol?                 [2] 
 
9. Write the electrode reactions taking place in the Ni–Cd cell.      [2] 
 
10. For reaction: A + H2O ? B, Rate a [A], what is its           [2] 
(a) Molecularity 
(b) Order of reaction 
 
 
11. Give a chemical test to distinguish between the following pairs of compounds.          [2] 
(a)  
 
 
(b)  
 
 
12. Classify the following as addition and condensation polymers:     [2] 
terylene, Bakelite, polyvinyl chloride, polyethene 
 
 
Section C 
 
13. Draw the structures of isomers, if any, and write the names of the following complexes:   [3] 
(a) [Cr(NH3)4Cl2]
+
 
(b) [Co(en)3]
3+
 
(c) [CoCl2(en)2]Cl 
     
14. Examine the illustration of a portion of the defective crystal and answer the following 
questions:                                                                                                                                                      [3]                                                                                           
                  
                                                   
(a) What are these types of valency defects called? 
(b) How is the density of a crystal affected by these defects? 
(c) Name one ionic compound which can show this type of 
defect in the crystalline state. 
                                                                                                                                             
  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
15. What method would you suggest for the separation of metals in the following mixtures? [3] 
(a) Zinc and iron 
(b) Copper and magnesium 
(c) Rare earth 
OR 
 
Write the reactions taking place in the different zones in the blast furnace during the 
extraction of iron. 
 
16. 18 g of glucose, C6H12O6, is dissolved in 1 kg of water in a saucepan. At what temperature 
will water boil at 1.013 bar? (Kb for water is 0.52 K kg mol
-1
.)     [3] 
 
OR 
 
Why is the boiling point of a solution containing a non-volatile solute more than that of pure 
solvent? Explain graphically. 
 
17.                                         [3] 
(a) Give the mechanism of acid-catalysed dehydration of ethanol to yield ethyne. 
(b) Compound (A) C4H10O is found to be soluble in sulphuric acid. (A) does not react with 
sodium metal or potassium permanganate. When it is heated with excess of HI, it is 
converted to a single alkyl halide. What is the structural formula of (A)? 
 
18. It is observed that the rate of a chemical reaction doubles with every 10
°
 rise in 
temperature. If this generalisation holds good for a reaction in the temperature range 295–
305 K, what would be the volume of activation energy for this reaction?              [3] 
(R = 8.314 J/Kmol) 
 
19.                                                         [3] 
(a) Give two reasons to support the cyclic structure of glucose. 
(b) Why are amino acids soluble in water? 
(c) Name the pyrimidine bases present in DNA and RNA. 
 
 
20. Explain the following observations:         [3] 
(a) Lyophilic colloid is more stable than lyophobic colloid. 
(b) Coagulation takes place when sodium chloride solution is added to a colloidal solution of 
ferric hydroxide. 
(c) The sky appears blue in colour. 
 
 
21.                                                [3] 
(a) Distinguish between 
(i) Aniline and benzyl amine                                   
(ii) CH3CH2NH2 and (CH3)2NH                              
(b) Write a note on the Hoffmann bromamide reaction.  
 
  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
22.                                     [3] 
(a) Why do transition metals form complex compounds?                                             
(b) What is lanthanoid contraction? 
(c) Why does Cr have a high melting point? 
 
 
23. Arrange the following in order of increasing reactivity in SN1 and SN2 reactions:   [3] 
C6H5CH2Br, C6H5CH (C6H5) Br, C6H5CH (CH3) Br, C6H5C (CH3) (C6H5) Br  
  
OR 
  
        What happens when                                                                                                     
(a) Chloroethane is made to react with KCN. 
(b) 1-Bromopropane reacts with silver acetate.  
             Give equations involved. 
 
24. What are antihistamines? Give an example. Discuss their working in the human body. [3] 
 
OR 
            
Account for the following: 
(a) Aspirin drug helps in the prevention of heart attack. 
(b) Diabetic patients are advised to take artificial sweeteners instead of natural 
sweeteners.  
(c)  Detergents are non-biodegradable, while soaps are biodegradable. 
 
 
Section D 
 
25.   Complete the equations:          [5]                                                                                               
(a) NaCl + MnO2 + H2SO4  
(b) Al + O2  
(c)  
(d) C + H 2SO4 (conc.)   
(e) PbS + O3  
OR 
           
Complete the equations: 
(a) NH4Cl(aq)  + NaNO2(aq)  
(b) P4  +  NaOH  +  H2O  
(c) CaF2  + H2SO4   
(d) NaOH (conc. hot)  + Cl2   
(e) PCl3  +  H2O   
 
 
?
?
? ? ? ? ?
673 K
32
2Pb(NO )   
?
?
?
?
?
?
?
  
 
CBSE XII  |  Chemistry  
Sample Paper 2 
 
     
26.              [5] 
(a) Decomposition of a compound follows first order kinetics. It takes 15 min for 20% of 
the starting compound to react. Calculate 
(i) Rate constant for the reaction. 
(ii) Time at which 10% of the reactant is left unreacted.  
(iii) Time taken for the next 20% of the reactant to react after the first 15 min.                                                              
(b) Derive a relationship between rate constant and half-life for a zero-order reaction.   
 
OR 
 
(a) The rates of a reaction starting with initial concentrations 2.0 × 10
-3
 M and 1.0 × 10
-3 
M are equal to 2.40 × 10
-4
 M s
-1
 and 0.60 × 10
-4
 M s
-1
, respectively. Calculate the 
order of the reaction with respect to the reactant and also the rate constant.     
(b) For a reaction A + B  C, it is found that      
(i) Rate becomes double when concentration of A is doubled. 
(ii) Rate becomes 16 times when concentration of both A and B are doubled. 
(iii)  Write the rate expression and calculate the overall order of the reaction. 
  
                                                                                     
27.                                                          [5] 
(a) Convert:  
(i) Acetic acid to ethylamine 
(ii) Propionic acid to lactic acid 
 
(b) Identify A, B and C in the following reactions: 
            
 
OR 
 
(a) Convert: 
(i) Acetaldehyde to crotonic acid 
(ii) Formaldehyde to chloroethane 
(iii) Acetic acid to propanoic acid 
 
(b) Identify A and B in the given equation: 
               
 
 
?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
42
LiAlH SOCl KOH(alc)
33
CH COCH A B  C      
? ? ? ? ? ? ? 
Conc.NaOH
HCHO A   + B