CBSE Chemistry Past year paper - 2017, Class 12 Class 12 Notes | EduRev

Chemistry Class 12

Class 12 : CBSE Chemistry Past year paper - 2017, Class 12 Class 12 Notes | EduRev

 Page 1


  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
CBSE 
Class XII Chemistry 
Board Paper – 2017 
 
Time: 3 Hours  Total Marks: 70                                                                            
  
General Instructions:                                                                                                                     
(i) All questions are compulsory. 
(ii) Question numbers 1 to 5 are very short answer questions and carry 1 mark 
each. 
(iii) Question numbers 6 to 10 are short answer questions and carry 2 marks 
each. 
(iv) Question numbers 11 to 22 are also short answer questions and carry 3 
marks each. 
(v) Question number 23 is a value based question and carries 4 marks. 
(vi) Question numbers 24 to 26 are long answer questions and carry 5 marks 
each. 
(vii) Use log tables, if necessary. Use of calculators is not allowed. 
 
 
1. Write the formula of an oxo-anion of Manganese (Mn) in which it shows the 
oxidation state equal to its group number. [1] 
 
2. Write IUPAC name of the following compound-:  
(CH3CH2)2NCH3 [1] 
 
3. For a reaction R ? P, half-life (t1/2) is observed to be independent of the initial 
concentration of reactants. What is the order of reaction? [1] 
 
4. Write the structure of 1-Bromo-4-chlorobut-2-ene. [1] 
 
5. Write one similarity between Physisorption and Chemisorption. [1] 
 
6. Complete the following reactions: [1+1=2] 
(i) NH3 + 3Cl2 (excess) ? 
(ii) XeF6 + 2H2O ? 
                        OR  
What happens when  
(i) (NH4)2Cr2O7 is heated?  
(ii) H3PO3 is heated?  
Write the equations.  
 
7. Define the following terms:  [1+1=2] 
(i) Colligative properties  
(ii) Molality (m)  
Page 2


  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
CBSE 
Class XII Chemistry 
Board Paper – 2017 
 
Time: 3 Hours  Total Marks: 70                                                                            
  
General Instructions:                                                                                                                     
(i) All questions are compulsory. 
(ii) Question numbers 1 to 5 are very short answer questions and carry 1 mark 
each. 
(iii) Question numbers 6 to 10 are short answer questions and carry 2 marks 
each. 
(iv) Question numbers 11 to 22 are also short answer questions and carry 3 
marks each. 
(v) Question number 23 is a value based question and carries 4 marks. 
(vi) Question numbers 24 to 26 are long answer questions and carry 5 marks 
each. 
(vii) Use log tables, if necessary. Use of calculators is not allowed. 
 
 
1. Write the formula of an oxo-anion of Manganese (Mn) in which it shows the 
oxidation state equal to its group number. [1] 
 
2. Write IUPAC name of the following compound-:  
(CH3CH2)2NCH3 [1] 
 
3. For a reaction R ? P, half-life (t1/2) is observed to be independent of the initial 
concentration of reactants. What is the order of reaction? [1] 
 
4. Write the structure of 1-Bromo-4-chlorobut-2-ene. [1] 
 
5. Write one similarity between Physisorption and Chemisorption. [1] 
 
6. Complete the following reactions: [1+1=2] 
(i) NH3 + 3Cl2 (excess) ? 
(ii) XeF6 + 2H2O ? 
                        OR  
What happens when  
(i) (NH4)2Cr2O7 is heated?  
(ii) H3PO3 is heated?  
Write the equations.  
 
7. Define the following terms:  [1+1=2] 
(i) Colligative properties  
(ii) Molality (m)  
  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
8. Draw the structures of the following:  [1+1=2] 
(i) H2S2O7  
(ii) XeF6  
 
9. Calculate the degree of dissociation ( a) of acetic acid if its molar conductivity 
( ?m) is 39.05 S cm
2 
mol
?1
. [2] 
Given ?
o 
(H
+
) = 349.6 S cm
2
 mol
?1
 and ?
o
 (CH3COO
?
) = 40.9 S cm
2
 mol
?1
  
 
10. Write the equations involved in the following reactions: [2] 
(i) Wolff-Kishner reduction 
(ii) Etard reaction  
 
11. A 10% solution (by mass) of sucrose in water has freezing point of 269.15 K 
Calculate the freezing point of 10% glucose in water, if freezing point of pure 
water is 273.15 K. [3] 
Given: (Molar mass of sucrose = 342 g mol
?1
) 
          (Molar mass of glucose = 180 g mol
?1
)  
12.  
(a) Calculate the mass of Ag deposited at cathode when a current of 2 amperes was 
passed through a solution of AgNO3 for 15 minutes. [2+1=3] 
(Given: Molar mass of Ag = 108 g mol
?1
 1F = 96500 C mol
?1
) 
(b) Define fuel cell.  
 
13.  
i. What type of isomerism is shown by the complex [Co(NH3)6] [Cr(CN)6]?[1 ?3=3] 
ii. Why a solution of [Ni(H2O)6]
2+
 is green while a solution of [Ni(CN)4]
2 ?
 is 
colourless? (At. no. of Ni = 28)  
iii. Write the IUPAC name of the following complex: [Co(NH3)5(CO3)]Cl  
 
14. Write one difference in each of the following:  [1 ?3=3] 
(i) Lyophobic sol and Lyophilic sol  
(ii) Solution and Colloid  
(iii) Homogeneous catalysis and Heterogeneous catalysis  
  
15. Following data are obtained for the reaction: [3] 
N2O5 ? 2NO2 + ½ O2 
 
t/s 0 300 600 
[N2O5]/mol L
?1
 1.6 ? 10
?2 
0.8 ? 10
?2 
0.4 ? 10
?2 
 
  
Page 3


  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
CBSE 
Class XII Chemistry 
Board Paper – 2017 
 
Time: 3 Hours  Total Marks: 70                                                                            
  
General Instructions:                                                                                                                     
(i) All questions are compulsory. 
(ii) Question numbers 1 to 5 are very short answer questions and carry 1 mark 
each. 
(iii) Question numbers 6 to 10 are short answer questions and carry 2 marks 
each. 
(iv) Question numbers 11 to 22 are also short answer questions and carry 3 
marks each. 
(v) Question number 23 is a value based question and carries 4 marks. 
(vi) Question numbers 24 to 26 are long answer questions and carry 5 marks 
each. 
(vii) Use log tables, if necessary. Use of calculators is not allowed. 
 
 
1. Write the formula of an oxo-anion of Manganese (Mn) in which it shows the 
oxidation state equal to its group number. [1] 
 
2. Write IUPAC name of the following compound-:  
(CH3CH2)2NCH3 [1] 
 
3. For a reaction R ? P, half-life (t1/2) is observed to be independent of the initial 
concentration of reactants. What is the order of reaction? [1] 
 
4. Write the structure of 1-Bromo-4-chlorobut-2-ene. [1] 
 
5. Write one similarity between Physisorption and Chemisorption. [1] 
 
6. Complete the following reactions: [1+1=2] 
(i) NH3 + 3Cl2 (excess) ? 
(ii) XeF6 + 2H2O ? 
                        OR  
What happens when  
(i) (NH4)2Cr2O7 is heated?  
(ii) H3PO3 is heated?  
Write the equations.  
 
7. Define the following terms:  [1+1=2] 
(i) Colligative properties  
(ii) Molality (m)  
  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
8. Draw the structures of the following:  [1+1=2] 
(i) H2S2O7  
(ii) XeF6  
 
9. Calculate the degree of dissociation ( a) of acetic acid if its molar conductivity 
( ?m) is 39.05 S cm
2 
mol
?1
. [2] 
Given ?
o 
(H
+
) = 349.6 S cm
2
 mol
?1
 and ?
o
 (CH3COO
?
) = 40.9 S cm
2
 mol
?1
  
 
10. Write the equations involved in the following reactions: [2] 
(i) Wolff-Kishner reduction 
(ii) Etard reaction  
 
11. A 10% solution (by mass) of sucrose in water has freezing point of 269.15 K 
Calculate the freezing point of 10% glucose in water, if freezing point of pure 
water is 273.15 K. [3] 
Given: (Molar mass of sucrose = 342 g mol
?1
) 
          (Molar mass of glucose = 180 g mol
?1
)  
12.  
(a) Calculate the mass of Ag deposited at cathode when a current of 2 amperes was 
passed through a solution of AgNO3 for 15 minutes. [2+1=3] 
(Given: Molar mass of Ag = 108 g mol
?1
 1F = 96500 C mol
?1
) 
(b) Define fuel cell.  
 
13.  
i. What type of isomerism is shown by the complex [Co(NH3)6] [Cr(CN)6]?[1 ?3=3] 
ii. Why a solution of [Ni(H2O)6]
2+
 is green while a solution of [Ni(CN)4]
2 ?
 is 
colourless? (At. no. of Ni = 28)  
iii. Write the IUPAC name of the following complex: [Co(NH3)5(CO3)]Cl  
 
14. Write one difference in each of the following:  [1 ?3=3] 
(i) Lyophobic sol and Lyophilic sol  
(ii) Solution and Colloid  
(iii) Homogeneous catalysis and Heterogeneous catalysis  
  
15. Following data are obtained for the reaction: [3] 
N2O5 ? 2NO2 + ½ O2 
 
t/s 0 300 600 
[N2O5]/mol L
?1
 1.6 ? 10
?2 
0.8 ? 10
?2 
0.4 ? 10
?2 
 
  
  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
(a) Show that it follows first order reaction.  
(b) Calculate the half-life. 
(Given log 2 = 0.3010, log 4 =0.6021)  
 
16. Following compounds are given to you:  [1 ?3=3] 
2-Bromopentane, 2-Bmmo-2-methylbutane, 1-Bromopentane 
(i) Write the compound which is most reactive towards SN2 reaction. 
(ii) Write the compound which is optically active.  
(iii) Write the compound which is most reactive towards ?-elimination reaction. 
  
17.  
(a) Write the principle of method used for the refining of germanium. [1 ?3=3] 
(b) Out of PbS and PbCO3 (ores of lead), which one is concentrated by froth floatation 
process preferably? 
(c) What is the significance of leaching in the extraction of aluminium?  
 
18. Write structures of compounds A, B and C in each of the following reactions :[
1
1
2
?2=3] 
 
2(g) 5
3
2
3
(a)CO PCl Mg/dryether
65
(b)H O
(a)SnCl /HCl dil.NaOH
3
(b)H O
(i) C H Br A B C
(ii) CH CN A B C
?
?
?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
  
OR 
Do the following conversions in not more than two steps: [1 ?3=3] 
(i) Benzoic acid to Benzaldehyde 
(ii) Ethyl benzene to Benzoic acid 
(iii) Propanone to Propene   
 
19. Write the structures of the monomers used for getting the following polymers:[1 ?3=3] 
(i) Dacron 
(ii) Melamine –formaldehyde polymer 
(iii) Buna –N   
 
20. Define the following: [1 ?3=3] 
(i) Anionic detergents 
(ii) Broad spectrum antibiotics 
(iii) Antiseptic  
 
21. Given reasons: [1 ?3=3] 
(i) Thermal stability decreases from H2O to H2Te. 
(ii) Fluoride ion has higher hydration enthalpy than chloride ion. 
(iii) Nitrogen does not form pentahalide.   
  
Page 4


  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
CBSE 
Class XII Chemistry 
Board Paper – 2017 
 
Time: 3 Hours  Total Marks: 70                                                                            
  
General Instructions:                                                                                                                     
(i) All questions are compulsory. 
(ii) Question numbers 1 to 5 are very short answer questions and carry 1 mark 
each. 
(iii) Question numbers 6 to 10 are short answer questions and carry 2 marks 
each. 
(iv) Question numbers 11 to 22 are also short answer questions and carry 3 
marks each. 
(v) Question number 23 is a value based question and carries 4 marks. 
(vi) Question numbers 24 to 26 are long answer questions and carry 5 marks 
each. 
(vii) Use log tables, if necessary. Use of calculators is not allowed. 
 
 
1. Write the formula of an oxo-anion of Manganese (Mn) in which it shows the 
oxidation state equal to its group number. [1] 
 
2. Write IUPAC name of the following compound-:  
(CH3CH2)2NCH3 [1] 
 
3. For a reaction R ? P, half-life (t1/2) is observed to be independent of the initial 
concentration of reactants. What is the order of reaction? [1] 
 
4. Write the structure of 1-Bromo-4-chlorobut-2-ene. [1] 
 
5. Write one similarity between Physisorption and Chemisorption. [1] 
 
6. Complete the following reactions: [1+1=2] 
(i) NH3 + 3Cl2 (excess) ? 
(ii) XeF6 + 2H2O ? 
                        OR  
What happens when  
(i) (NH4)2Cr2O7 is heated?  
(ii) H3PO3 is heated?  
Write the equations.  
 
7. Define the following terms:  [1+1=2] 
(i) Colligative properties  
(ii) Molality (m)  
  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
8. Draw the structures of the following:  [1+1=2] 
(i) H2S2O7  
(ii) XeF6  
 
9. Calculate the degree of dissociation ( a) of acetic acid if its molar conductivity 
( ?m) is 39.05 S cm
2 
mol
?1
. [2] 
Given ?
o 
(H
+
) = 349.6 S cm
2
 mol
?1
 and ?
o
 (CH3COO
?
) = 40.9 S cm
2
 mol
?1
  
 
10. Write the equations involved in the following reactions: [2] 
(i) Wolff-Kishner reduction 
(ii) Etard reaction  
 
11. A 10% solution (by mass) of sucrose in water has freezing point of 269.15 K 
Calculate the freezing point of 10% glucose in water, if freezing point of pure 
water is 273.15 K. [3] 
Given: (Molar mass of sucrose = 342 g mol
?1
) 
          (Molar mass of glucose = 180 g mol
?1
)  
12.  
(a) Calculate the mass of Ag deposited at cathode when a current of 2 amperes was 
passed through a solution of AgNO3 for 15 minutes. [2+1=3] 
(Given: Molar mass of Ag = 108 g mol
?1
 1F = 96500 C mol
?1
) 
(b) Define fuel cell.  
 
13.  
i. What type of isomerism is shown by the complex [Co(NH3)6] [Cr(CN)6]?[1 ?3=3] 
ii. Why a solution of [Ni(H2O)6]
2+
 is green while a solution of [Ni(CN)4]
2 ?
 is 
colourless? (At. no. of Ni = 28)  
iii. Write the IUPAC name of the following complex: [Co(NH3)5(CO3)]Cl  
 
14. Write one difference in each of the following:  [1 ?3=3] 
(i) Lyophobic sol and Lyophilic sol  
(ii) Solution and Colloid  
(iii) Homogeneous catalysis and Heterogeneous catalysis  
  
15. Following data are obtained for the reaction: [3] 
N2O5 ? 2NO2 + ½ O2 
 
t/s 0 300 600 
[N2O5]/mol L
?1
 1.6 ? 10
?2 
0.8 ? 10
?2 
0.4 ? 10
?2 
 
  
  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
(a) Show that it follows first order reaction.  
(b) Calculate the half-life. 
(Given log 2 = 0.3010, log 4 =0.6021)  
 
16. Following compounds are given to you:  [1 ?3=3] 
2-Bromopentane, 2-Bmmo-2-methylbutane, 1-Bromopentane 
(i) Write the compound which is most reactive towards SN2 reaction. 
(ii) Write the compound which is optically active.  
(iii) Write the compound which is most reactive towards ?-elimination reaction. 
  
17.  
(a) Write the principle of method used for the refining of germanium. [1 ?3=3] 
(b) Out of PbS and PbCO3 (ores of lead), which one is concentrated by froth floatation 
process preferably? 
(c) What is the significance of leaching in the extraction of aluminium?  
 
18. Write structures of compounds A, B and C in each of the following reactions :[
1
1
2
?2=3] 
 
2(g) 5
3
2
3
(a)CO PCl Mg/dryether
65
(b)H O
(a)SnCl /HCl dil.NaOH
3
(b)H O
(i) C H Br A B C
(ii) CH CN A B C
?
?
?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
  
OR 
Do the following conversions in not more than two steps: [1 ?3=3] 
(i) Benzoic acid to Benzaldehyde 
(ii) Ethyl benzene to Benzoic acid 
(iii) Propanone to Propene   
 
19. Write the structures of the monomers used for getting the following polymers:[1 ?3=3] 
(i) Dacron 
(ii) Melamine –formaldehyde polymer 
(iii) Buna –N   
 
20. Define the following: [1 ?3=3] 
(i) Anionic detergents 
(ii) Broad spectrum antibiotics 
(iii) Antiseptic  
 
21. Given reasons: [1 ?3=3] 
(i) Thermal stability decreases from H2O to H2Te. 
(ii) Fluoride ion has higher hydration enthalpy than chloride ion. 
(iii) Nitrogen does not form pentahalide.   
  
  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
22. Given reasons: [1 ?3=3] 
(i) Acetylation of aniline reduces its activation effect. 
(ii) CH3NH2 is more basic than C6H5NH2. 
(iii)  Although –NH2 is o/p directing group, yet aniline on nitration gives a significant 
amount of m-nitroaniline.   
 
23. After watching a programme on TV about the presence of carcinogens (cancer 
causing agents) Potassium bromate and Potassium iodate in bread and other bakery 
product, Ritu a class XII student decided to aware others about the adverse effects 
of these carcinogens in foods. She consulted the school principal and requested him 
to instruct canteen contractor to stop selling sandwiches, pizza, burgers and other 
bakery products to the students. Principal took an immediate action and instructed 
the canteen contractor to replace the bakery products with some proteins and 
vitamins rich food like fruits, salads, sprouts etc. The decision was welcomed by the 
parents and students.  [4] 
After reading the above passage, answer the following questions:  
(i) What are the values (at least two) displayed by Ritu?  
(ii) Which polysaccharide component of carbohydrates is commonly present 
in bread? 
(iii) Write the two types of secondary structure of proteins.  
(iv) Give two examples of water soluble vitamins.  
 
24.   
(a) Account for the following: [3+2=5] 
(i) Transition metals form large number of complex compounds. 
(ii) The lowest oxide of transition metal is basic whereas the highest 
oxide is amphoteric or acidic. 
(iii) E 
o 
value for the Mn
3+
/Mn
2+
 couple is highly positive (+1.57 V) as 
compare to Cr
3+
/Cr
2+
. 
 
(b) Write one similarity and one difference between the chemistry of 
lanthanoid and actinoid elements. 
 
OR 
(a)  
(i) How is the variability in oxidation states of transition metals different 
from that of p-block elements? 
(ii) Out of Cu
+
 and Cu
2+
, which ion is unstable in aqueous solution and 
why? 
(iii) Orange colour of Cr2O7
2 ?
 ion change to yellow when treated with an 
alkali. Why? 
 
(b) Chemistry of actinoids is complicated as compared to lanthanoids. Give two 
reasons.  
  
Page 5


  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
CBSE 
Class XII Chemistry 
Board Paper – 2017 
 
Time: 3 Hours  Total Marks: 70                                                                            
  
General Instructions:                                                                                                                     
(i) All questions are compulsory. 
(ii) Question numbers 1 to 5 are very short answer questions and carry 1 mark 
each. 
(iii) Question numbers 6 to 10 are short answer questions and carry 2 marks 
each. 
(iv) Question numbers 11 to 22 are also short answer questions and carry 3 
marks each. 
(v) Question number 23 is a value based question and carries 4 marks. 
(vi) Question numbers 24 to 26 are long answer questions and carry 5 marks 
each. 
(vii) Use log tables, if necessary. Use of calculators is not allowed. 
 
 
1. Write the formula of an oxo-anion of Manganese (Mn) in which it shows the 
oxidation state equal to its group number. [1] 
 
2. Write IUPAC name of the following compound-:  
(CH3CH2)2NCH3 [1] 
 
3. For a reaction R ? P, half-life (t1/2) is observed to be independent of the initial 
concentration of reactants. What is the order of reaction? [1] 
 
4. Write the structure of 1-Bromo-4-chlorobut-2-ene. [1] 
 
5. Write one similarity between Physisorption and Chemisorption. [1] 
 
6. Complete the following reactions: [1+1=2] 
(i) NH3 + 3Cl2 (excess) ? 
(ii) XeF6 + 2H2O ? 
                        OR  
What happens when  
(i) (NH4)2Cr2O7 is heated?  
(ii) H3PO3 is heated?  
Write the equations.  
 
7. Define the following terms:  [1+1=2] 
(i) Colligative properties  
(ii) Molality (m)  
  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
8. Draw the structures of the following:  [1+1=2] 
(i) H2S2O7  
(ii) XeF6  
 
9. Calculate the degree of dissociation ( a) of acetic acid if its molar conductivity 
( ?m) is 39.05 S cm
2 
mol
?1
. [2] 
Given ?
o 
(H
+
) = 349.6 S cm
2
 mol
?1
 and ?
o
 (CH3COO
?
) = 40.9 S cm
2
 mol
?1
  
 
10. Write the equations involved in the following reactions: [2] 
(i) Wolff-Kishner reduction 
(ii) Etard reaction  
 
11. A 10% solution (by mass) of sucrose in water has freezing point of 269.15 K 
Calculate the freezing point of 10% glucose in water, if freezing point of pure 
water is 273.15 K. [3] 
Given: (Molar mass of sucrose = 342 g mol
?1
) 
          (Molar mass of glucose = 180 g mol
?1
)  
12.  
(a) Calculate the mass of Ag deposited at cathode when a current of 2 amperes was 
passed through a solution of AgNO3 for 15 minutes. [2+1=3] 
(Given: Molar mass of Ag = 108 g mol
?1
 1F = 96500 C mol
?1
) 
(b) Define fuel cell.  
 
13.  
i. What type of isomerism is shown by the complex [Co(NH3)6] [Cr(CN)6]?[1 ?3=3] 
ii. Why a solution of [Ni(H2O)6]
2+
 is green while a solution of [Ni(CN)4]
2 ?
 is 
colourless? (At. no. of Ni = 28)  
iii. Write the IUPAC name of the following complex: [Co(NH3)5(CO3)]Cl  
 
14. Write one difference in each of the following:  [1 ?3=3] 
(i) Lyophobic sol and Lyophilic sol  
(ii) Solution and Colloid  
(iii) Homogeneous catalysis and Heterogeneous catalysis  
  
15. Following data are obtained for the reaction: [3] 
N2O5 ? 2NO2 + ½ O2 
 
t/s 0 300 600 
[N2O5]/mol L
?1
 1.6 ? 10
?2 
0.8 ? 10
?2 
0.4 ? 10
?2 
 
  
  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
(a) Show that it follows first order reaction.  
(b) Calculate the half-life. 
(Given log 2 = 0.3010, log 4 =0.6021)  
 
16. Following compounds are given to you:  [1 ?3=3] 
2-Bromopentane, 2-Bmmo-2-methylbutane, 1-Bromopentane 
(i) Write the compound which is most reactive towards SN2 reaction. 
(ii) Write the compound which is optically active.  
(iii) Write the compound which is most reactive towards ?-elimination reaction. 
  
17.  
(a) Write the principle of method used for the refining of germanium. [1 ?3=3] 
(b) Out of PbS and PbCO3 (ores of lead), which one is concentrated by froth floatation 
process preferably? 
(c) What is the significance of leaching in the extraction of aluminium?  
 
18. Write structures of compounds A, B and C in each of the following reactions :[
1
1
2
?2=3] 
 
2(g) 5
3
2
3
(a)CO PCl Mg/dryether
65
(b)H O
(a)SnCl /HCl dil.NaOH
3
(b)H O
(i) C H Br A B C
(ii) CH CN A B C
?
?
?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
  
OR 
Do the following conversions in not more than two steps: [1 ?3=3] 
(i) Benzoic acid to Benzaldehyde 
(ii) Ethyl benzene to Benzoic acid 
(iii) Propanone to Propene   
 
19. Write the structures of the monomers used for getting the following polymers:[1 ?3=3] 
(i) Dacron 
(ii) Melamine –formaldehyde polymer 
(iii) Buna –N   
 
20. Define the following: [1 ?3=3] 
(i) Anionic detergents 
(ii) Broad spectrum antibiotics 
(iii) Antiseptic  
 
21. Given reasons: [1 ?3=3] 
(i) Thermal stability decreases from H2O to H2Te. 
(ii) Fluoride ion has higher hydration enthalpy than chloride ion. 
(iii) Nitrogen does not form pentahalide.   
  
  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
22. Given reasons: [1 ?3=3] 
(i) Acetylation of aniline reduces its activation effect. 
(ii) CH3NH2 is more basic than C6H5NH2. 
(iii)  Although –NH2 is o/p directing group, yet aniline on nitration gives a significant 
amount of m-nitroaniline.   
 
23. After watching a programme on TV about the presence of carcinogens (cancer 
causing agents) Potassium bromate and Potassium iodate in bread and other bakery 
product, Ritu a class XII student decided to aware others about the adverse effects 
of these carcinogens in foods. She consulted the school principal and requested him 
to instruct canteen contractor to stop selling sandwiches, pizza, burgers and other 
bakery products to the students. Principal took an immediate action and instructed 
the canteen contractor to replace the bakery products with some proteins and 
vitamins rich food like fruits, salads, sprouts etc. The decision was welcomed by the 
parents and students.  [4] 
After reading the above passage, answer the following questions:  
(i) What are the values (at least two) displayed by Ritu?  
(ii) Which polysaccharide component of carbohydrates is commonly present 
in bread? 
(iii) Write the two types of secondary structure of proteins.  
(iv) Give two examples of water soluble vitamins.  
 
24.   
(a) Account for the following: [3+2=5] 
(i) Transition metals form large number of complex compounds. 
(ii) The lowest oxide of transition metal is basic whereas the highest 
oxide is amphoteric or acidic. 
(iii) E 
o 
value for the Mn
3+
/Mn
2+
 couple is highly positive (+1.57 V) as 
compare to Cr
3+
/Cr
2+
. 
 
(b) Write one similarity and one difference between the chemistry of 
lanthanoid and actinoid elements. 
 
OR 
(a)  
(i) How is the variability in oxidation states of transition metals different 
from that of p-block elements? 
(ii) Out of Cu
+
 and Cu
2+
, which ion is unstable in aqueous solution and 
why? 
(iii) Orange colour of Cr2O7
2 ?
 ion change to yellow when treated with an 
alkali. Why? 
 
(b) Chemistry of actinoids is complicated as compared to lanthanoids. Give two 
reasons.  
  
  
 
CBSE XII  | CHEMISTRY 
Board Paper – 2017 
 
     
25.  
(a) An element has atomic mass 93 g mol
?1
 and density 11.5 g cm
?3
. If the 
       edge length of its units cell is 300 pm, identify the type of unit cell.  [3+2=5] 
(b) Write any two differences between amorphous solids and crystalline solids.   
 
OR 
 
(a) Calculate the number of units cells in 8.1 g of aluminium if it crystallizes in a f.c.c. 
structure. (Atomic mass of Al=27 g mol
?1
) [2+3=5] 
(b) Give reasons: 
(i) In stoichiometric defects, NaCl exhibits Schottky defect and not 
Frenkel defect. 
(ii) Silicon on doping with Phosphorus forms n-type semiconductor. 
(iii) Ferrimagnetic substances show better magnetism than antiferromagnetic 
substances.  
 
26.  
(a) Write the product (s) in the following reactions:  [3+2=5] 
(i)  
 
 
(ii)  
HI
3 2 3
CH CH O CH CH ? ?
CH
3
|
? ? ? ? ? ? ? ? ? 
 
(iii)  
PCC
32
CH CH CH CH OH ? ? ? ? ? ? ? ? ? 
           
         
(b) Given simple chemical tests to distinguish between the following pairs of 
compounds: 
(i) Ethanol and Phenol  
(ii) Propanol and 2-methylpropan-2-ol  
 
OR 
 
(a) Write the formula of reagents used in the following reactions: 
(i) Bromination of phenol to 2, 4, 6-tribromophenol 
(ii) Hydroborations of propene and then oxidation to propanol. 
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