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Page 1 MS CLASS XII CHEMISTRY 2019-20 Q.No. Value points Marks SECTION:A 1. Reaction taking place at cathode when the battery is in use: ) ( 2 ) ( 2 ) ( 4 ) ( ) ( 2 4 2 4 2 l O H s PbSO e aq H aq SO s PbO ? ? ? ? ? ? ? ? 1 2. 2 F 1 3. M Molarity 02 . 5 100 98 1000 294 . 1 38 ? ? ? ? ? 1 4. It can be recharged after use. 1 5. At anode: O 2 (g) At cathode: H 2 (g) ½ ½ 6. Sodium cyanide. 1 7. Nucleotide 1 8. Zwitterion / dipolar ion 1 9. Condensation 1 10. Benzaldehyde 1 11. (c) 1 12. (b) 1 13. (b) 1 14. (a) 1 15. (b) 1 16. (c) 1 17. (a) 1 18. (d) 1 19. (d) 1 20. (d) 1 SECTION:B 21. Lone pairs : 2 Geometry : Square planar 1 1 22. (i) (ii) R E Slope a 303 . 2 ? ? k 1 > k 2 1 1 23. When there is dissociation of solute into ions, in dilute solutions (ignoring interionic attractions) the number of particles increases. As the value of colligative properties depends on the number of particles of the solute , the experimentally observed value of colligative property will be higher than the true value, therefore the experimentally determined (observed) molar mass is always lower than the true value. For KCl(electrolyte) the experimentally determined molar mass is always 1 ½ Page 2 MS CLASS XII CHEMISTRY 2019-20 Q.No. Value points Marks SECTION:A 1. Reaction taking place at cathode when the battery is in use: ) ( 2 ) ( 2 ) ( 4 ) ( ) ( 2 4 2 4 2 l O H s PbSO e aq H aq SO s PbO ? ? ? ? ? ? ? ? 1 2. 2 F 1 3. M Molarity 02 . 5 100 98 1000 294 . 1 38 ? ? ? ? ? 1 4. It can be recharged after use. 1 5. At anode: O 2 (g) At cathode: H 2 (g) ½ ½ 6. Sodium cyanide. 1 7. Nucleotide 1 8. Zwitterion / dipolar ion 1 9. Condensation 1 10. Benzaldehyde 1 11. (c) 1 12. (b) 1 13. (b) 1 14. (a) 1 15. (b) 1 16. (c) 1 17. (a) 1 18. (d) 1 19. (d) 1 20. (d) 1 SECTION:B 21. Lone pairs : 2 Geometry : Square planar 1 1 22. (i) (ii) R E Slope a 303 . 2 ? ? k 1 > k 2 1 1 23. When there is dissociation of solute into ions, in dilute solutions (ignoring interionic attractions) the number of particles increases. As the value of colligative properties depends on the number of particles of the solute , the experimentally observed value of colligative property will be higher than the true value, therefore the experimentally determined (observed) molar mass is always lower than the true value. For KCl(electrolyte) the experimentally determined molar mass is always 1 ½ lower than the true value when water is used as solvent. Glucose (non-electrolyte) does not show a large variation from the true value. ½ 24. (a) (b) CH3-CH(Cl)-COOH C6H5CHO 1 1 25. IUPAC Name of the entity: Dichloridobis(ethane-1,2-diamine)platinum(IV) ion OR Bonding in ? 3 6 3 ] ) ( [ NH CO d 2 sp 3 hybridisation Geometry: Octahedral Diamagnetic 1 1 ½ ½ ½ ½ 26. Vapour phase refining: It is a refining method in which the metal is converted into its volatile compound and collected elsewhere. It is then decomposed to give pure metal. Example:Mond’s Process for refining of Nickel / van Arkel method for refining of Zirconium 1 1 Page 3 MS CLASS XII CHEMISTRY 2019-20 Q.No. Value points Marks SECTION:A 1. Reaction taking place at cathode when the battery is in use: ) ( 2 ) ( 2 ) ( 4 ) ( ) ( 2 4 2 4 2 l O H s PbSO e aq H aq SO s PbO ? ? ? ? ? ? ? ? 1 2. 2 F 1 3. M Molarity 02 . 5 100 98 1000 294 . 1 38 ? ? ? ? ? 1 4. It can be recharged after use. 1 5. At anode: O 2 (g) At cathode: H 2 (g) ½ ½ 6. Sodium cyanide. 1 7. Nucleotide 1 8. Zwitterion / dipolar ion 1 9. Condensation 1 10. Benzaldehyde 1 11. (c) 1 12. (b) 1 13. (b) 1 14. (a) 1 15. (b) 1 16. (c) 1 17. (a) 1 18. (d) 1 19. (d) 1 20. (d) 1 SECTION:B 21. Lone pairs : 2 Geometry : Square planar 1 1 22. (i) (ii) R E Slope a 303 . 2 ? ? k 1 > k 2 1 1 23. When there is dissociation of solute into ions, in dilute solutions (ignoring interionic attractions) the number of particles increases. As the value of colligative properties depends on the number of particles of the solute , the experimentally observed value of colligative property will be higher than the true value, therefore the experimentally determined (observed) molar mass is always lower than the true value. For KCl(electrolyte) the experimentally determined molar mass is always 1 ½ lower than the true value when water is used as solvent. Glucose (non-electrolyte) does not show a large variation from the true value. ½ 24. (a) (b) CH3-CH(Cl)-COOH C6H5CHO 1 1 25. IUPAC Name of the entity: Dichloridobis(ethane-1,2-diamine)platinum(IV) ion OR Bonding in ? 3 6 3 ] ) ( [ NH CO d 2 sp 3 hybridisation Geometry: Octahedral Diamagnetic 1 1 ½ ½ ½ ½ 26. Vapour phase refining: It is a refining method in which the metal is converted into its volatile compound and collected elsewhere. It is then decomposed to give pure metal. Example:Mond’s Process for refining of Nickel / van Arkel method for refining of Zirconium 1 1 Equations involved: 4 350 330 ) ( 4 CO Ni CO Ni K ? ? ? ? ? ? ? CO Ni CO Ni K 4 ) ( 470 450 4 ? ? ? ? ? ? ? OR Extraction of gold involves leaching the metal with CN - Oxidation reaction: 4 Au (s) + 8 CN- (aq.) + 2H 2 O (aq.) + O 2 (g) ?4[Au(CN) 2 ] - (aq.) + 4 OH - (aq.) The metal is recovered by displacement method: 2[Au(CN) 2 ]- (aq.) + Zn (s) ? 2 Au (s) + [Zn(CN) 4 ] 2- (aq.) Zinc acts as a reducing agent. ½ ½ ½ ½ ½ ½ 27. The following compound will undergo S N 1 faster: CH 2 Cl Greater the stability of the carbocation, greater will be its ease of formation from the corresponding halide and faster will be the rate of reaction. The benzylic carbocation formed gets stabilised through resonance. CH 3 CH 2 CH 2 Cl forms a 1 0 carbocation, which is less stable than benzylic carbocation. ½ ½ ½ ½ SECTION :C 28. KCl ? K + + Cl - n =2 ? ? ? ? ? ? ? ? 1 1 i n i ½ ½ ½ Page 4 MS CLASS XII CHEMISTRY 2019-20 Q.No. Value points Marks SECTION:A 1. Reaction taking place at cathode when the battery is in use: ) ( 2 ) ( 2 ) ( 4 ) ( ) ( 2 4 2 4 2 l O H s PbSO e aq H aq SO s PbO ? ? ? ? ? ? ? ? 1 2. 2 F 1 3. M Molarity 02 . 5 100 98 1000 294 . 1 38 ? ? ? ? ? 1 4. It can be recharged after use. 1 5. At anode: O 2 (g) At cathode: H 2 (g) ½ ½ 6. Sodium cyanide. 1 7. Nucleotide 1 8. Zwitterion / dipolar ion 1 9. Condensation 1 10. Benzaldehyde 1 11. (c) 1 12. (b) 1 13. (b) 1 14. (a) 1 15. (b) 1 16. (c) 1 17. (a) 1 18. (d) 1 19. (d) 1 20. (d) 1 SECTION:B 21. Lone pairs : 2 Geometry : Square planar 1 1 22. (i) (ii) R E Slope a 303 . 2 ? ? k 1 > k 2 1 1 23. When there is dissociation of solute into ions, in dilute solutions (ignoring interionic attractions) the number of particles increases. As the value of colligative properties depends on the number of particles of the solute , the experimentally observed value of colligative property will be higher than the true value, therefore the experimentally determined (observed) molar mass is always lower than the true value. For KCl(electrolyte) the experimentally determined molar mass is always 1 ½ lower than the true value when water is used as solvent. Glucose (non-electrolyte) does not show a large variation from the true value. ½ 24. (a) (b) CH3-CH(Cl)-COOH C6H5CHO 1 1 25. IUPAC Name of the entity: Dichloridobis(ethane-1,2-diamine)platinum(IV) ion OR Bonding in ? 3 6 3 ] ) ( [ NH CO d 2 sp 3 hybridisation Geometry: Octahedral Diamagnetic 1 1 ½ ½ ½ ½ 26. Vapour phase refining: It is a refining method in which the metal is converted into its volatile compound and collected elsewhere. It is then decomposed to give pure metal. Example:Mond’s Process for refining of Nickel / van Arkel method for refining of Zirconium 1 1 Equations involved: 4 350 330 ) ( 4 CO Ni CO Ni K ? ? ? ? ? ? ? CO Ni CO Ni K 4 ) ( 470 450 4 ? ? ? ? ? ? ? OR Extraction of gold involves leaching the metal with CN - Oxidation reaction: 4 Au (s) + 8 CN- (aq.) + 2H 2 O (aq.) + O 2 (g) ?4[Au(CN) 2 ] - (aq.) + 4 OH - (aq.) The metal is recovered by displacement method: 2[Au(CN) 2 ]- (aq.) + Zn (s) ? 2 Au (s) + [Zn(CN) 4 ] 2- (aq.) Zinc acts as a reducing agent. ½ ½ ½ ½ ½ ½ 27. The following compound will undergo S N 1 faster: CH 2 Cl Greater the stability of the carbocation, greater will be its ease of formation from the corresponding halide and faster will be the rate of reaction. The benzylic carbocation formed gets stabilised through resonance. CH 3 CH 2 CH 2 Cl forms a 1 0 carbocation, which is less stable than benzylic carbocation. ½ ½ ½ ½ SECTION :C 28. KCl ? K + + Cl - n =2 ? ? ? ? ? ? ? ? 1 1 i n i ½ ½ ½ C T T T T T m iK T f f f f f f f 0 ' ' 0 24 . 0 24 . 0 100 5 . 74 1000 5 . 0 86 . 1 ) 92 . 0 1 ( ? ? ? ? ? ? ? ? ? ? ? x x x x ½ ½ ½ 29. ) .......( ] 1 . 0 [ ] 2 . 0 [ 10 . 0 ) ......( ] 1 . 0 [ ] 1 . 0 [ 05 . 0 ] [ ] [ ii k i k B A k rate y x y x y x ? ? ? 1 ) 2 ( 05 . 0 10 . 0 ) ( ) ( ) ......( ] 2 . 0 [ ] 1 . 0 [ 05 . 0 ? ? ? ? x i ii iii k x y x 0 ) 2 ( 05 . 0 05 . 0 ) ( ) ( ? ? ? y i iii y 0 1 ] [ ] [ B A k rate ? It is a first order reaction. s t k t s o A rate k 386 . 1 5 . 0 693 . 0 693 . 0 5 . ] [ 2 1 2 1 1 ? ? ? ? ? ? OR 2 300 50 693 . 0 350 25 693 . 0 693 . 0 1 2 1 2 2 1 ? ? ? ? k k K k K k k t ½ ½ ½ ½ ½ ½ ½ ½ Page 5 MS CLASS XII CHEMISTRY 2019-20 Q.No. Value points Marks SECTION:A 1. Reaction taking place at cathode when the battery is in use: ) ( 2 ) ( 2 ) ( 4 ) ( ) ( 2 4 2 4 2 l O H s PbSO e aq H aq SO s PbO ? ? ? ? ? ? ? ? 1 2. 2 F 1 3. M Molarity 02 . 5 100 98 1000 294 . 1 38 ? ? ? ? ? 1 4. It can be recharged after use. 1 5. At anode: O 2 (g) At cathode: H 2 (g) ½ ½ 6. Sodium cyanide. 1 7. Nucleotide 1 8. Zwitterion / dipolar ion 1 9. Condensation 1 10. Benzaldehyde 1 11. (c) 1 12. (b) 1 13. (b) 1 14. (a) 1 15. (b) 1 16. (c) 1 17. (a) 1 18. (d) 1 19. (d) 1 20. (d) 1 SECTION:B 21. Lone pairs : 2 Geometry : Square planar 1 1 22. (i) (ii) R E Slope a 303 . 2 ? ? k 1 > k 2 1 1 23. When there is dissociation of solute into ions, in dilute solutions (ignoring interionic attractions) the number of particles increases. As the value of colligative properties depends on the number of particles of the solute , the experimentally observed value of colligative property will be higher than the true value, therefore the experimentally determined (observed) molar mass is always lower than the true value. For KCl(electrolyte) the experimentally determined molar mass is always 1 ½ lower than the true value when water is used as solvent. Glucose (non-electrolyte) does not show a large variation from the true value. ½ 24. (a) (b) CH3-CH(Cl)-COOH C6H5CHO 1 1 25. IUPAC Name of the entity: Dichloridobis(ethane-1,2-diamine)platinum(IV) ion OR Bonding in ? 3 6 3 ] ) ( [ NH CO d 2 sp 3 hybridisation Geometry: Octahedral Diamagnetic 1 1 ½ ½ ½ ½ 26. Vapour phase refining: It is a refining method in which the metal is converted into its volatile compound and collected elsewhere. It is then decomposed to give pure metal. Example:Mond’s Process for refining of Nickel / van Arkel method for refining of Zirconium 1 1 Equations involved: 4 350 330 ) ( 4 CO Ni CO Ni K ? ? ? ? ? ? ? CO Ni CO Ni K 4 ) ( 470 450 4 ? ? ? ? ? ? ? OR Extraction of gold involves leaching the metal with CN - Oxidation reaction: 4 Au (s) + 8 CN- (aq.) + 2H 2 O (aq.) + O 2 (g) ?4[Au(CN) 2 ] - (aq.) + 4 OH - (aq.) The metal is recovered by displacement method: 2[Au(CN) 2 ]- (aq.) + Zn (s) ? 2 Au (s) + [Zn(CN) 4 ] 2- (aq.) Zinc acts as a reducing agent. ½ ½ ½ ½ ½ ½ 27. The following compound will undergo S N 1 faster: CH 2 Cl Greater the stability of the carbocation, greater will be its ease of formation from the corresponding halide and faster will be the rate of reaction. The benzylic carbocation formed gets stabilised through resonance. CH 3 CH 2 CH 2 Cl forms a 1 0 carbocation, which is less stable than benzylic carbocation. ½ ½ ½ ½ SECTION :C 28. KCl ? K + + Cl - n =2 ? ? ? ? ? ? ? ? 1 1 i n i ½ ½ ½ C T T T T T m iK T f f f f f f f 0 ' ' 0 24 . 0 24 . 0 100 5 . 74 1000 5 . 0 86 . 1 ) 92 . 0 1 ( ? ? ? ? ? ? ? ? ? ? ? x x x x ½ ½ ½ 29. ) .......( ] 1 . 0 [ ] 2 . 0 [ 10 . 0 ) ......( ] 1 . 0 [ ] 1 . 0 [ 05 . 0 ] [ ] [ ii k i k B A k rate y x y x y x ? ? ? 1 ) 2 ( 05 . 0 10 . 0 ) ( ) ( ) ......( ] 2 . 0 [ ] 1 . 0 [ 05 . 0 ? ? ? ? x i ii iii k x y x 0 ) 2 ( 05 . 0 05 . 0 ) ( ) ( ? ? ? y i iii y 0 1 ] [ ] [ B A k rate ? It is a first order reaction. s t k t s o A rate k 386 . 1 5 . 0 693 . 0 693 . 0 5 . ] [ 2 1 2 1 1 ? ? ? ? ? ? OR 2 300 50 693 . 0 350 25 693 . 0 693 . 0 1 2 1 2 2 1 ? ? ? ? k k K k K k k t ½ ½ ½ ½ ½ ½ ½ ½ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 300 350 300 350 314 . 8 303 . 2 2 log 1 1 303 . 2 log 2 1 1 2 x x a a E T T R E k k Ea = 12.104 kJ / mol. ½ ½ (1/2 +1/2) 30. (a) (b) (c) K 4 [Fe(CN) 6 ] Fe(OH) 3 is converted into colloidal state by preferential adsorption of Fe 3+ ions. Proteins 1 1 1 31. (a) (b) (c) Moist sulphur dioxide behaves as a reducing agent, reduces MnO 4 - to Mn 2+ . X –X’ bond in interhalogens is weaker than X-X bond in halogensexcept F- F bond. Due to the ease with which it liberates atoms of nascent oxygen. 1 1 1 32. 1-Propoxypropane is formed. Mechanism involved: Step 1 :Formation of protonated alcohol 1 ½ 1 ½ 33. (a) (i)Read More
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