Chemistry Standard Level Specimen Paper 1A 2025 PDF

SPEC/4/CHEMI/SPM/ENG/TZ0/XX Chemistry Standard level Paper 1A Specimen paper 1 hour 30 minutes [Paper 1A and Paper 1B] Instructions to candidates y Do not open this examination paper until instructed to do so. y Answer all questions. y For each question, choose the answer you consider to be the...

SPEC/4/CHEMI/SPM/ENG/TZ0/XX Chemistry Standard level Paper 1A Specimen paper 1 hour 30 minutes [Paper 1A and Paper 1B] Instructions to candidates y Do not open this examination paper until instructed to do so. y Answer all questions. y For each question, choose the answer you consider to be the best and indicate your choice on the answer sheet provided. y A calculator is required for this paper. y A clean copy of the chemistry data booklet is required for this paper. y The maximum mark for paper 1A is [30 marks]. y The maximum mark for paper 1A and paper 1B is [55 marks]. 0000 – 6104 11 pages © International Baccalaureate Organization 2023  SPEC/4/CHEMI/SPM/ENG/TZ0/XX –2– 0000 – 6104 Section A 1. Which technique is used to purify a solid obtained from a chemical reaction? A. distillation B. evaporation C. recrystallization D. filtration 2. Ice containing only the isotope 2H sinks and does not melt when dropped into ordinary distilled water maintained at 3 C. Which statement is correct? A. The isotope 2H has a high natural abundance. 2 B. H2O (s) has a higher melting point than normal ice. 2 C. H2O (s) has a lower density than normal ice-cold water. 2 D. H2O has different chemical properties from normal water. 3. Which electron transition in the hydrogen atom emits radiation with the highest energy? A. n = 1 to n = 2 B. n = 2 to n = 3 C. n = 2 to n = 1 D. n = 3 to n = 2 4. A container holds 30 g of argon and 60 g of neon. What is the ratio of number of atoms of argon to number of atoms of neon in the container? A. 0.25 B. 0.50 C. 2.0 D. 4.0  SPEC/4/CHEMI/SPM/ENG/TZ0/XX –3– 0000 – 6104 5. A gas storage tank of fixed volume V contains N molecules of an ideal gas at 300 K with a N pressure of 40 kPa. molecules are removed, and the temperature is changed to 450 K. 4 What is the new pressure of the gas in kPa? A. 15 B. 30 C. 45 D. 60 6. What is the formula of the compound formed between magnesium ions and hydrogencarbonate ions? ↑ A. MgHCO3 G B. Mg(HCO3)2 C. Mg(HCO3)3 D. Mg3(HCO3)2 7. Which species contains a coordination bond? A. CO2 B. HCN C. NO2+ D. NO3− 8. Which properties depend on the movement of the delocalized electrons in a metal? I. Electrical conductivity II. Thermal conductivity III. Density A. I and II only · B. I and III only C. II and III only D. I, II and III Turn over  SPEC/4/CHEMI/SPM/ENG/TZ0/XX –4– 0000 – 6104 9. Which substance, made from two elements with electronegativities EX and EY, is an alloy? Average electronegativity Electronegativity difference EX + EY EX − EY 2 A. 2.5 2.5 B. 2.5 1.0 C. 3.5 0.2 D. 1.2 0.2 10. Which structure shows the repeating unit of the polymer formed by but-1-ene? H H H CH3 H A. C C C C. C C H H CH3 H CH3 H H H H B. C C D. C C CH3 CH3 H CH2 CH3 11. What is the explanation for the malleability of metals? A. The bonds are strong. ~ B. The bonds are weak. C. The bonds involve free electrons. D. The bonds do not have a specific direction.  SPEC/4/CHEMI/SPM/ENG/TZ0/XX –5– 0000 – 6104 12. Which functional groups are present in this molecule? A. amino, alkoxy, ester B. ether, carboxyl, amino C. carboxyl, alkoxy, ester D. ester, amino, carboxyl 13. In which block of the periodic table would element 119 be placed, if it is found in the future? A. s B. p C. d D. f Turn over  SPEC/4/CHEMI/SPM/ENG/TZ0/XX –6– 0000 – 6104 X Which is a correct alternative representation of this molecule? 14. H Cl H C H H C C Cl H C H A. C3H6Cl2 B. Cl Cl C. 2,2-dichlorobut-1-ene D. CH3CHClC(Cl)=CH2 15. The block structure of the periodic table groups elements according to which characteristic? A. atomic number B. atomic mass C. electron configuration D. reactivity 16. Which set of conditions describe a reaction in which the reactants are more stable than the products? A. endothermic and ∆H negative B. endothermic and ∆H positive C. exothermic and ∆H negative D. exothermic and ∆H positive  SPEC/4/CHEMI/SPM/ENG/TZ0/XX –7– 0000 – 6104 17. Which enthalpy changes can be calculated using only bond enthalpy data? I. N2 (g) + 2H2 (g) → N2H4 (g) II. CH4 (g) + 2O2 (g) → 2H2O (l) + CO2 (g) III. H2 (g) + Cl2 (g) → 2HCl (g) A. I and II only B. I and III only C. II and III only D. I, II and III 18. Which is a renewable energy source? A. natural gas B. uranium C. coal D. wood 19. What is the amount, in mol, of H2O produced for a reaction between 10.0 mol of C2H3Cl and 10.0 mol of O2 if the yield is 90 %? : 2C2H3Cl (g) + 5O2 (g) → 4CO2 (g) + 2H2O (g) + 2HCl (g) A. 3.60 B. 4.00 C. 9.00 D. 10.00 20. The complete combustion of 20.0 cm3 of a gaseous hydrocarbon, CxHy, produces 80.0 cm3 of gaseous products. This volume reduces to 40.0 cm3 when the water vapour present condenses. All volumes are measured at the same temperature and pressure. What is the molecular formula of the hydrocarbon? A. CH4 B. C 2H 2 C. C 2H 4 D. C 3H 6 Turn over  SPEC/4/CHEMI/SPM/ENG/TZ0/XX –8– 0000 – 6104 2 21. Large deposits of methane hydrate, CH4⋅6H2O (Mr = 124), have been discovered under the ocean floor. What mass of carbon dioxide would be produced by the complete combustion of 12.4 g of the methane hydrate? A. 4.40 g B. 26.4 g C. 34.1 g D. 44.0 g 22. The diagram shows the energy profile of a reaction. Potential energy Products Y Reactants Z X Reaction coordinate Which combination is correct? Activation energy of Activation energy of forward reaction reverse reaction A. X Z B. Y−X Y−Z C. Y Y D. Y−X Z−X  SPEC/4/CHEMI/SPM/ENG/TZ0/XX –9– 0000 – 6104 23. What is the main reason for an increase in rate of reaction when the temperature is raised? A. A greater proportion of collisions are successful. Texo B. Particles collide more frequently. C. The bonds in the reactants are weakened. D. The activation energy of the reaction decreases. 24. What is the equilibrium constant expression for the following reaction? 2SO3 (g)  2SO2 (g) + O2 (g) [SO2 ]2 [O2 ] A. [SO3 ]2 [SO2 ]2 + [O2 ] B. [SO3 ]2 [SO3 ]2 C. [SO2 ]2 [O2 ] 2[SO2 ][O2 ] D. 2[SO3 ] 25. Which reactions involve the transfer of a proton? I. 2HCl (aq) + Mg (s) → MgCl2 (aq) + H2 (g) II. 2HCl (aq) + MgO (s) → MgCl2 (aq) + H2O (l) III. 2HCl (aq) + MgCO3 (s) → MgCl2 (aq) + H2O (l) + CO2 (g) A. I and II only B. I and III only C. ↑ II and III only D. I, II and III Turn over  SPEC/4/CHEMI/SPM/ENG/TZ0/XX – 10 – 0000 – 6104 26. The overall reaction occurring at the electrodes of a rechargeable metal hydride battery can be summarized as: MH + NiO(OH)  M + Ni(OH)2 Which statement is correct? A. The oxidation state of Ni does not change. B. M is oxidized by loss of hydrogen. C. The oxidation state of one H atom changes from −1 to +1. D. The oxidation state of one O atom changes from −1 to −2. 27. In a redox titration, manganate(VII) ions are reduced to manganese(II) ions and iron(II) ions are oxidized to iron(III) ions. 100 MnO4− (aq) reduced to Mn2+ (aq) 100 20 Fe2+ (aq) oxidized to Fe3+ (aq) What volume, in cm3, of 0.1 mol dm−3 MnO4− (aq) is required to reach the equivalence point in the titration of 20.00 cm3 of 0.1 mol dm−3 Fe2+ (aq)? A. 2.00 B. 4.00 C. 20.00 D. 100.00 28. What is the organic product of the reaction of 1-chloropentane with aqueous sodium hydroxide? A. pentan-1-ol B. 1-chloropentan-1-ol C. 1-chloropent-1-ene D. 1-chloropent-2-ene  SPEC/4/CHEMI/SPM/ENG/TZ0/XX – 11 – 0000 – 6104 29. Which statements explain the following reactions occurring in the upper atmosphere? Chlorofluorocarbon (CFC) compounds A single chlorine radical breaks down break down to produce chlorine radicals many ozone, O3, molecules. but usually not fluorine radicals. chain propagation steps produce more A. C–Cl bond is stronger than C–F bond radicals chain termination steps cause chlorine B. C–F bond is stronger than C–Cl bond radicals to reform chlorine molecules chain termination steps cause chlorine C. C–Cl bond is stronger than C–F bond radicals to reform chlorine molecules chain propagation steps produce more D. C–F bond is stronger than C–Cl bond radicals 30. Which species can act as an electrophile? A. CH4 B. Cl2 C. Cl− D. OH− S  Markscheme Specimen paper Chemistry Standard level Paper 1 – Section A 2 pages  –2– 1. C 16. B 31. – 46. – 2. B 17. B 32. – 47. – 3. C 18. D 33. – 48. – 4. A 19. A 34. – 49. – 5. C 20. C 35. – 50. – 6. B 21. A 36. – 51. – 7. D 22. B 37. – 52. – 8. A 23. A 38. – 53. – 9. D 24. A 39. – 54. – 10. D 25. C 40. – 55. – 11. D 26. C 41. – 56. – 12. A 27. B 42. – 57. – 13. A 28. A 43. – 58. – 14. D 29. D 44. – 59. – 15. C 30. B 45. – 60. –  Markscheme Specimen paper Chemistry Standard level Paper 2 10 pages  –4– Question Answers Notes Total 39.99 g nC = « = » 3.33 «mol» 12.01gmol−1 6.73 g nH = « = » 6.66 «mol» 1. (a) 1.01gmol−1 2 53.28 g nO= « = =» 3.33 «mol»  16.00 gmol−1 CH2O  nHX (= nNaOH =) 0.750 «mol dm-3» × 0.02230 «dm3» / 0.0167 «mol»  1. (b) 1.51 g Accept 90.3 «g mol–1». 2 MHX = ( = ) 90.4 g mol-1  0.0167mol Accept consistent feasible structural 1. (c) C3H6O3  1 formula. 1. (d) carboxyl/COOH  Do not accept “carbonyl/C=O”. 1  –5– Question Answers Notes Total 2. (a) (i) Gold: +79 AND Helium: +2  1 2. (a) (ii) repelled by «hitting/close contact with» gold nucleus  1 atom is mainly empty space/vacuum 2. (a) (iii) OR 1 nucleus is very small «compared to the size of the atom»  2. (b) (i) discrete/series of lines of different frequency/wavelength  1 energy of photon relates to a frequency «in the spectrum»  2. (b) (ii) 2 energy of photon depends on difference in energy levels  H half/lower nuclear charge/number of protons  2. (b) (iii) 2 H larger/double radius  2. (b) (iv) electron-electron interactions «need to be taken in account»  1 Any one of: new evidence 2. (c) new technology 1 developments in related models models incomplete/failed to account for all observations   –6– Question Answers Notes Total separate curves/lines for Li and K sketched AND both increasing  steeper gradient for Li 3. (a) 2 OR curve/line for Li higher  3. (b) equal masses «of different substances» do not contain equal amounts/moles  1 «Avg electronegativity = 1.8 Δ electronegativity = 1.6» 3. (c) 2 % covalent character = 45-55  ionic  [:C≡C:]2- 3. (d) 2- charge  2 :C≡C:   –7– Question Answers Notes Total 4. (a) C17H36(l) + 26O2(g) → 17CO2(g) + 18H2O(l)  1 2.00 g 2.00 g nC17H36 = « = =» 4. (b) (i) [(17 × 12.01g mol ) + (36 × 1.01g mol )] 240.53 g mol−1 −1 −1 2 0.008315/0.00831 «mol»  « energy = 11350 kJ mol-1 × 0.008315 mol = » 94.4 «kJ»  94 400 = 500.0 × 4.18 × ∆T  4. (b) (ii) 2 ∆T = 45.2«K»  Any two: water does not evaporate  heat is not lost to the surroundings OR 4. (b) (iii) 2 max all heat is transferred to the water  density of water is 1 g cm-3  water is pure  complete combustion   –8– Question Answers Notes Total CO2 consumed while plant is growing «and later released when biofuel is combusted» 4. (c) 1 OR photosynthesis uses up CO2 «later released when biofuel is combusted»  bonds broken: 4(C ̶ C ) / 4 × 346  bonds formed: 2(C=C) / 2 × 614  4. (d) Award for correct final answer. 3 ΔHϴ = «4 × 346 – 2 × 614 / 1384 – 1228 =» «+»156 «kJ»  4. (e) C2H4(g) + H2O(g) → C2H5OH(g)  1 4. (f) (i) H2O / water  1 «20(12.01) + 38(1.01) + 2(16.00) = 310.58 100 × 310.58 4. (f) (ii) = 1 (310.58 + 18.02) » 94.5 %  Any two of: sustainable development  4. (f) (iii) more economical/efficient  2 max better use of natural resources  reduces waste   –9– Question Answers Notes Total → 2 Cl 5. (a) (i) Accept chlorine atoms. 2 2 Cl  single-barbed/fish-hooks  → 5. (a) (ii) 1 full/double-barbed arrow AND charges on both ions are required for mark.  5. (a) (iii) Cl+ AND can accept a pair of electrons to form a new bond  1  – 10 – Question Answers Notes Total 5. (b) (i) hydrogen bonding stronger than dipole-dipole  1 «increase because» stronger London/dispersion forces  more electrons 5. (b) (ii) 2 OR surface contact  5. (c) (i) 3 start at pH = 1  curve with decreasing gradient  must finish below pH = 7  5. (c) (ii) 12  1 SPEC/4/CHEMI/HPM/ENG/TZ0/XX Chemistry Higher level Paper 1A Specimen paper 2 hours [Paper 1A and Paper 1B] Instructions to candidates y Do not open this examination paper until instructed to do so. y Answer all questions. y For each question, choose the answer you consider to be the best and indicate your choice on the answer sheet provided. y A calculator is required for this paper. y A clean copy of the chemistry data booklet is required for this paper. y The maximum mark for paper 1A is [40 marks]. y The maximum mark for paper 1A and paper 1B is [75 marks]. 0000 – 6101 14 pages © International Baccalaureate Organization 2023  SPEC/4/CHEMI/HPM/ENG/TZ0/XX –2– 0000 – 6101 Section A 1. What is thin-layer chromatography best used for separating? A. molecules of varying polarity B. molecules of similar polarity C. metals in an alloy D. water of crystallization from hydrated salts 2. Ice containing only the isotope 2H sinks and does not melt when dropped into ordinary distilled water maintained at 3 C. Which statement is correct? A. The isotope 2H has a high natural abundance. 2 B. H2O (s) has a higher melting point than normal ice. 2 C. H2O (s) has a lower density than normal ice-cold water. 2 D. H2O has different chemical properties from normal water. 3. The table lists successive ionization energies of an element Z. Ionization number 1st 2nd 3rd 4th 5th 6th Ionization energy / kJ mol−1 577.54 1816.68 2744.78 11 577.5 14 841.9 18 379.0 Which is the formula of the stable oxide of the element Z? A. Z2O B. ZO C. Z2O3 D. ZO2  SPEC/4/CHEMI/HPM/ENG/TZ0/XX –3– 0000 – 6101 4. A container holds 30 g of argon and 60 g of neon. What is the ratio of number of atoms of argon to number of atoms of neon in the container? A. 0.25 B. 0.50 C. 2.0 D. 4.0 5. A gas storage tank of fixed volume V contains N molecules of an ideal gas at 300 K with a N pressure of 40 kPa. molecules are removed, and the temperature is changed to 450 K. 4 What is the new pressure of the gas in kPa? A. 15 B. 30 C. 45 D. 60 6. What is the formula of the compound formed between magnesium ions and hydrogencarbonate ions? A. MgHCO3 B. Mg(HCO3)2 C. Mg(HCO3)3 D. Mg3(HCO3)2 7. In which group of ions and molecules are electrons delocalized in all species? A. CH3COOH, O3, C60 B. CH3COO−, NO2−, C(graphite) C. C2H2, (COOH)2, C(diamond) D. C2H4, NO2+, SiO2 Turn over  SPEC/4/CHEMI/HPM/ENG/TZ0/XX –4– 0000 – 6101 8. What is the molecular geometry of the central atom in SF4Cl2? A. linear B. tetrahedral C. hexagonal D. octahedral 9. Which is the preferred Lewis formula of nitrous oxide, N2O, as deduced by formal charges? A. N N O B. N N O C. N N O D. N O N 10. Which pair of statements about electrons in this molecule is correct? O H N H O H Number of non-bonding Number of electrons in pairs of electrons π bonds A. 3 6 B. 3 8 C. 5 6 D. 5 8 11. What is the explanation for the malleability of metals? A. The bonds are strong. B. The bonds are weak. C. The bonds involve free electrons. D. The bonds do not have a specific direction.  SPEC/4/CHEMI/HPM/ENG/TZ0/XX –5– 0000 – 6101 12. The structure shows the repeating unit of a polymer found in some plastics. CH3 CH2 C CH3 Which monomer is used to form this plastic? A. H2C=C(CH3)2 B. CH3CH(CH3)2 C. (H3C)2C=C(CH3)2 D. (H3C)2C=CHCH(CH3)2 13. Why is copper(II) sulfate blue? A. Red light is absorbed when electrons are promoted between the orbitals in the split d-sublevels. B. Blue light is emitted when electrons fall between the orbitals in the split d-sublevels. C. Red light is absorbed when electrons fall between the orbitals in the split d-sublevels. D. Blue light is emitted when electrons are promoted between the orbitals in the split d-sublevels. 14. Which molecule has a carbonyl functional group? A. CH3OCH3 B. CH3COCH3 C. CH3CH2OH D. CH3CH2NH2 15. The block structure of the periodic table groups elements according to which characteristic? A. atomic number B. atomic mass C. electron configuration D. reactivity Turn over  SPEC/4/CHEMI/HPM/ENG/TZ0/XX –6– 0000 – 6101 16. Which d block element has the highest number of different oxidation states? A. Ti B. Mn C. Cu D. Zn 17. What do all greenhouse gases have in common? A. They are emitted by the burning of fossil fuels. B. They absorb ultraviolet radiation. C. They are symmetrical molecules with no polar bonds. D. They absorb infrared radiation. 18. Which is the 1H NMR spectrum of cyclohexane? A. C. 8 6 4 2 0 8 6 4 2 0 Chemical shift / ppm Chemical shift / ppm B. D. 8 6 4 2 0 8 6 4 2 0 Chemical shift / ppm Chemical shift / ppm  SPEC/4/CHEMI/HPM/ENG/TZ0/XX –7– 0000 – 6101 19. Which is the mass spectrum of butanal? A. 100 C. 100 Relative intensity Relative intensity 80 80 60 60 40 40 20 20 0 0 0 15 30 45 60 75 0 15 30 45 60 75 m/z m/z B. 100 D. 100 Relative intensity Relative intensity 80 80 60 60 40 40 20 20 0 0 0 15 30 45 60 75 0 15 30 45 60 75 m/z m/z 20. The potential energy profile for a “coffee cup” calorimetry experiment is shown. Thermometer Reactants Potential energy Products Coffee cup calorimeter Reaction coordinate What is the correct interpretation of this reaction? Temperature Type of reaction A. increases exothermic B. increases endothermic C. decreases exothermic D. decreases endothermic Turn over  SPEC/4/CHEMI/HPM/ENG/TZ0/XX –8– 0000 – 6101 21. What is the enthalpy change for the reaction in kJ mol−1? CO2 (g) + H2 (g) → CO (g) + H2O (g) 2CO (g) + O2 (g) → 2CO2 (g) ΔH = −566 kJ mol−1 2H2 (g) + O2 (g) → 2H2O (l) ΔH = −572 kJ mol−1 H2O (g) → H2O (l) ΔH = −44 kJ mol−1 A. −1182 B. −899 C. −41 D. +41 22. Which is a renewable energy source? A. natural gas B. uranium C. coal D. wood 23. Which are endothermic processes in a Born–Haber cycle for the formation of an ionic compound? I. Enthalpy of atomization II. First electron affinity III. First ionization energy A. I and II only B. I and III only C. II and III only D. I, II and III  SPEC/4/CHEMI/HPM/ENG/TZ0/XX –9– 0000 – 6101 24. What is correct as a system approaches equilibrium? A. Q remains constant. B. Kc increases. C. ΔGÖ becomes more negative. D. ΔG approaches zero. 25. The complete combustion of 20.0 cm3 of a gaseous hydrocarbon, CxHy, produces 80.0 cm3 of gaseous products. This volume reduces to 40.0 cm3 when the water vapour present condenses. All volumes are measured at the same temperature and pressure. What is the molecular formula of the hydrocarbon? A. CH4 B. C 2H 2 C. C 2H 4 D. C 3H 6 26. The diagram shows the energy profile of a reaction. Potential energy Products Y Reactants Z X Reaction coordinate Which combination is correct? Activation energy of Activation energy of forward reaction reverse reaction A. X Z B. Y−X Y−Z C. Y Y D. Y−X Z−X Turn over  SPEC/4/CHEMI/HPM/ENG/TZ0/XX – 10 – 0000 – 6101 27. What is the main reason for an increase in rate of reaction when the temperature is raised? A. A greater proportion of collisions are successful. B. Particles collide more frequently. C. The bonds in the reactants are weakened. D. The activation energy of the reaction decreases. 28. What is the equilibrium constant expression for the following reaction? 2SO3 (g)  2SO2 (g) + O2 (g) [SO2 ]2 [O2 ] A. [SO3 ]2 [SO2 ]2 + [O2 ] B. [SO3 ]2 [SO3 ]2 C. [SO2 ]2 [O2 ] 2[SO2 ][O2 ] D. 2[SO3 ] 29. Which statement is correct about points X and Y on the energy profile diagram? X Reactants Potential energy Y Products Reaction coordinate A. X is a transition state and Y is an intermediate. B. X is an intermediate and Y is a transition state. C. X and Y are transition states. D. X and Y are intermediates.  SPEC/4/CHEMI/HPM/ENG/TZ0/XX – 11 – 0000 – 6101 30. The equation for the reaction between two gases, A and B, is: A (g) + 2B (g)  2C (g) When the reaction is at equilibrium at 600 K, the concentrations of A, B, and C are 2, 1, and 2 mol dm−3 respectively. What is the value of the equilibrium constant at 600 K? A. 0.25 B. 1 C. 2 D. 4 31. Which reaction would be expected to have the largest Arrhenius (pre-exponential) factor, A, at constant temperature? A. H (g) + I (g) → HI (g) B. H2 (g) + I2 (g) → 2HI (g) C. 2HCl (g) → H2 (g) + Cl2 (g) D. H2 + C2H4 → C2H6 32. Which reactions involve the transfer of a proton? I. 2HCl (aq) + Mg (s) → MgCl2 (aq) + H2 (g) II. 2HCl (aq) + MgO (s) → MgCl2 (aq) + H2O (l) III. 2HCl (aq) + MgCO3 (s) → MgCl2 (aq) + H2O (l) + CO2 (g) A. I and II only B. I and III only C. II and III only D. I, II and III Turn over  SPEC/4/CHEMI/HPM/ENG/TZ0/XX – 12 – 0000 – 6101 33. The indicator, HInd, is used in an acid–base titration. HInd (aq)  H+ (aq) + Ind− (aq) colour A colour B Which statements are correct? I. In a strongly alkaline solution, colour B is observed. II. Colour A is observed when [HInd] < [Ind−]. III. [Ind−] approximately equals [HInd] at the end point. A. I and II only B. I and III only C. II and III only D. I, II and III 34. The overall reaction occurring at the electrodes of a rechargeable metal hydride battery can be summarized as: MH + NiO(OH)  M + Ni(OH)2 Which statement is correct? A. The oxidation state of Ni does not change. B. M is oxidized by loss of hydrogen. C. The oxidation state of one H atom changes from −1 to +1. D. The oxidation state of one O atom changes from −1 to −2. 35. In a redox titration, manganate(VII) ions are reduced to manganese(II) ions and iron(II) ions are oxidized to iron(III) ions. MnO4− (aq) reduced to Mn2+ (aq) Fe2+ (aq) oxidized to Fe3+ (aq) What volume, in cm3, of 0.1 mol dm−3 MnO4− (aq) is required to reach the equivalence point in the titration of 20.00 cm3 of 0.1 mol dm−3 Fe2+ (aq)? A. 2.00 B. 4.00 C. 20.00 D. 100.00  SPEC/4/CHEMI/HPM/ENG/TZ0/XX – 13 – 0000 – 6101 36. Which statements explain the following reactions occurring in the upper atmosphere? Chlorofluorocarbon (CFC) compounds A single chlorine radical breaks down break down to produce chlorine radicals many ozone, O3, molecules. but usually not fluorine radicals. chain propagation steps produce more A. C–Cl bond is stronger than C–F bond radicals chain termination steps cause chlorine B. C–F bond is stronger than C–Cl bond radicals to reform chlorine molecules chain termination steps cause chlorine C. C–Cl bond is stronger than C–F bond radicals to reform chlorine molecules chain propagation steps produce more D. C–F bond is stronger than C–Cl bond radicals 37. Which term cannot characterize ammonia, NH3? A. Lewis acid B. Brønsted–Lowry acid C. ligand D. nucleophile 38. Which ion is a better leaving group in nucleophilic substitutions? A. bromide ion B. chloride ion C. fluoride ion D. iodide ion 39. Which statement is correct when 2-chloro-2-methylpentane reacts with water to form 2-methylpentan-2-ol? A. Water acts as a nucleophile and attacks the chlorine atom. B. The reaction occurs in a single step. C. A carbocation intermediate is formed. D. Homolytic bond fission occurs. Turn over  SPEC/4/CHEMI/HPM/ENG/TZ0/XX – 14 – 0000 – 6101 40. Which illustrates the correct intermediate formed in the nitration of benzene by NO2+? H NO2 H NO2 A. C. H NO2 H NO2 B. D.  –2– 1. A 16. B 31. A 46. – 2. B 17. D 32. C 47. – 3. C 18. A 33. B 48. – 4. A 19. C 34. C 49. – 5. C 20. A 35. B 50. – 6. B 21. D 36. D 51. – 7. B 22. D 37. A 52. – 8. D 23. B 38. D 53. – 9. B 24. D 39. C 54. – 10. D 25. C 40. A 55. – 11. D 26. B 41. – 56. – 12. A 27. A 42. – 57. – 13. A 28. A 43. – 58. – 14. B 29. C 44. – 59. – 15. C 30. C 45. – 60. –