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Oxidation – Reduction Reactions · CSEC Chemistry

78 past-paper questions on Oxidation – Reduction Reactions, part of Principles of Chemistry, from every CSEC Chemistry paper on Quelpr.

Practise Oxidation – Reduction Reactions
  1. 1(a)2 marks· Chemistry Q1 1(a)List the apparatus that would be necessary to carry out the experiment.
  2. 1(b)9 marks· Chemistry Q1 1(b)Use the information in Figure 1 to complete Table 1.
  3. 1(c)(i)1 mark· Chemistry Q1 1(c)(i)Use an asterisk (*) to indicate the titration data that should be used to obtain the average titration volume of potassium dichromate used in the experiment.
  4. 1(c)(i)2 marks· Chemistry Q1 1(c)(i)Write a balanced half-equation to represent the change which takes place when Solution X reacts with aqueous iron(II) nitrate.
  5. 1(c)(ii)2 marks· Chemistry Q1 1(c)(ii)Hence, calculate the average volume of potassium dichromate used in the experiment and record the value to two decimal places.
  6. 1(c)(ii)2 marks· Chemistry Q1 1(c)(ii)Identify the oxidizing agent in the equation in (c) (i), and give a reason, in terms of oxidation numbers, why the agent is oxidizing.
  7. 1(c)(ii)3 marks· Chemistry Q1 1(c)(ii)Explain whether Solution X is behaving as a reducing agent, an oxidizing agent or both.
  8. 1(i)1 mark· Chemistry Q1 1(i)The reaction between iron and dichromate is considered a reduction-oxidation reaction. Define the term 'reduction' in terms of electrons.
  9. 1(i)2 marks· Chemistry Q1 1(i)What is the colour change at the endpoint of the titration of iron(II) sulfate with potassium manganate(VII)?
  10. 1(j)2 marks· Chemistry Q1 1(j)In the reaction, Fe²⁺ acts as a reducing agent. Define the term 'reducing agent'.
  11. 1(j)1 mark· Chemistry Q1 1(j)State ONE reason why there was no need to add an indicator to this titration.
  12. 1(k)2 marks· Chemistry Q1 1(k)Calculate the oxidation state of Cr in Cr₂O₇²⁻.
  13. 1(k)(ii)2 marks· Chemistry Q1 1(k)(ii)The resulting mixture from (i) was left to stand in air. Inference: Fe²⁺ ions oxidized to Fe³⁺.
  14. 1(l)1 mark· Chemistry Q1 1(l)State ONE precaution that should be taken when carrying out the experiment.
  15. 2(a)2 marks· Chemistry Q2 2(a)Distinguish between an 'oxidizing agent' and a 'reducing agent' in terms of electron gain or loss.
  16. 2(a)2 marks· Chemistry Q2 2(a)Based on the observed differences between Figures 2a and 2b, name TWO ions that would most likely be present in the beaker after three days.
  17. 2(a)1 mark· Chemistry Q2 2(a)Deduce the oxidation state of sulphur in CuSO4.
  18. 2(a)1 mark· Chemistry Q2 2(a)State ONE use of bleach in the laundering of clothing.
  19. 2(a)(i)2 marks· Chemistry Q2 2(a)(i)Classify Solution A as an oxidizing or a reducing agent in Experiments 1 and 2. Experiment 1: A is acting as... Experiment 2: A is acting as...
  20. 2(a)(i)1 mark· Chemistry Q2 2(a)(i)Define 'reduction' in terms of oxidation states.
  21. 2(a)(ii)4 marks· Chemistry Q2 2(a)(ii)Using the information given in Table 3 only, explain your answer to (a) (i) above. Experiment 1: Experiment 2:
  22. 2(a)(ii)1 mark· Chemistry Q2 2(a)(ii)Deduce the oxidation state of Cu in CuI.
  23. 2(a)(iii)2 marks· Chemistry Q2 2(a)(iii)Define the term 'oxidizing agent'.
  24. 2(a)(iv)2 marks· Chemistry Q2 2(a)(iv)With reference to the equation above, state, with a reason, which substance is acting as an oxidizing agent.
  25. 2(a)(v)1 mark· Chemistry Q2 2(a)(v)Solution A was added to a small portion of an aqueous solution of potassium iodide in a test tube. The colourless potassium iodide turned brown. State whether Solution A contained an oxidizing agent or a reducing agent.
  26. 2(a)(vi)2 marks· Chemistry Q2 2(a)(vi)Explain your answer in (a) (v).
  27. 2(a)(vii)2 marks· Chemistry Q2 2(a)(vii)Write a balanced chemical equation to show the formation of the brown product in the reaction in (a) (v).
  28. 2(b)4 marks· Chemistry Q2 2(b)Write ionic equation(s) to show the reactions that take place in the beaker in Figure 2b. Explain why these reactions occur.
  29. 2(b)(i)1 mark· Chemistry Q2 2(b)(i)Define, in terms of oxidation state, the term 'oxidizing agent'.
  30. 2(b)(i)1 mark· Chemistry Q2 2(b)(i)State an oxidizing agent that is NOT mentioned in Table 3.
  31. 2(b)(ii)2 marks· Chemistry Q2 2(b)(ii)Identify whether Solution C is acting as an oxidizing or reducing agent in Test 1 and Test 2.
  32. 2(b)(ii)1 mark· Chemistry Q2 2(b)(ii)Define, in terms of oxidation state, the term 'oxidation'.
  33. 2(b)(iii)4 marks· Chemistry Q2 2(b)(iii)With reference to oxidation states, explain EACH of your answers in (b) (ii).
  34. 2(c)1 mark· Chemistry Q2 2(c)Name the type of chemical reaction occurring in the experiment.
  35. 2(c)3 marks· Chemistry Q2 2(c)Deduce the oxidation number of Cl in the formula, NaClO.
  36. 2(c)2 marks· Chemistry Q2 2(c)One of the substances in the equation in (b) on page 11, is acting as a reducing agent. Describe a simple laboratory test that could be used to identify a reducing agent.
  37. 2(c)(i)2 marks· Chemistry Q2 2(c)(i)Write half-equations for the reactions occurring at the cathode.
  38. 2(c)(ii)1 mark· Chemistry Q2 2(c)(ii)Write half-equations for the reactions occurring at the anode.
  39. 2(d)1 mark· Chemistry Q2 2(d)From the equation written in (c) above, state whether the reaction at the anode is oxidation or reduction. Give an explanation for your answer.
  40. 2(d)2 marks· Chemistry Q2 2(d)Write a balanced equation for the reaction which occurs when chlorine is reacted with aqueous potassium iodide.
  41. 2(d)(i)2 marks· Chemistry Q2 2(d)(i)What is the change in oxidation number of Cl for the process?
  42. 2(d)(ii)1 mark· Chemistry Q2 2(d)(ii)Is this an oxidation or reduction process?
  43. 2(e)4 marks· Chemistry Q2 2(e)During one stage of the reaction, H₂O₂(aq) is converted to H₂O(l). Use the changes in oxidation number to determine whether this is an oxidation or reduction process.
  44. 2(e)(i)2 marks· Chemistry Q2 2(e)(i)the change in oxidation number that the iodide ions undergo
  45. 2(e)(ii)2 marks· Chemistry Q2 2(e)(ii)whether chlorine is acting as an oxidizing or a reducing agent. State a reason for your answer.
  46. 3(b)(i)1 mark· Chemistry Q3 3(b)(i)State the role of K2Cr2O7 in the conversion of D to E.
  47. 4(a)(i)4 marks· Chemistry Q4 4(a)(i)Identify the oxidizing and reducing agents in the equation, and explain your answer.
  48. 4(a)(iii)3 marks· Chemistry Q4 4(a)(iii)State whether the reaction in (ii) above is acid-base or redox, and explain your answer.
  49. 4(b)(i)4 marks· Chemistry Q4 4(b)(i)Write a balanced IONIC equation for the overall reaction, and identify the species being oxidised and reduced.
  50. 5(c)3 marks· Chemistry Q5 5(c)With reference to the gas produced when hydrochloric acid reacts with sodium sulphite, account for the observed changes in the acidified potassium manganate (VII) described in (b) (i) on page 14.
  51. 6(b)(iii)2 marks· Chemistry Q6 6(b)(iii)Account for the observations made from the reaction between the iron and copper sulfate solution.
  52. 6(c)(iii)2 marks· Chemistry Q6 6(c)(iii)With reference to the oxidation number of iodine, explain whether vitamin C is acting as an oxidizing or a reducing agent when it reacts with iodine.
  53. 3(c)3 marks· CSEC Chemistry · January 2002 · Paper 2State the chemical principles upon which the breath analyzer test for suspected drunken drivers is based.
  54. 3(f) [P2]5 marks· CSEC Chemistry · January 2002 · Paper 2What would you expect to observe if a solution of iron(III) chloride were warmed with a simple sugar and some aqueous sodium hydroxide added? Write TWO ionic equations to support your answer.
  55. Q111 mark · multiple choice· CSEC Chemistry · January 2017 · Paper 1When a compound is treated with concentrated hydrochloric acid, a greenish-yellow gas which bleaches moist red litmus paper is given off. The concentrated hydrochloric acid is acting as
  56. Q171 mark · multiple choice· CSEC Chemistry · January 2017 · Paper 1In which of the following compounds does hydrogen have a negative oxidation number?
  57. Q391 mark · multiple choice· CSEC Chemistry · January 2017 · Paper 1Which of the following ionic equations involves oxidation?
  58. Q161 mark · multiple choice· CSEC Chemistry · January 2018 · Paper 1The calcium ion has an oxidation number of +2 because the calcium atom has
  59. Q271 mark · multiple choice· CSEC Chemistry · January 2018 · Paper 1The oxidation number of silicon in \text{Na}_2\text{SiO}_3 is
  60. Q271 mark · multiple choice· CSEC Chemistry · January 2019 · Paper 1\text{FeCl}_2 and \text{FeCl}_3 are two chlorides of iron. Which of the following statements about these two chlorides of iron are true? I. The percentage of iron by mass in the two chlorides is different. II. The…
  61. Q251 mark · multiple choice· CSEC Chemistry · May/June 2010 · Paper 1A solution, when treated with the gas sulphur dioxide, becomes green. Which of the following does the solution contain?
  62. Q521 mark · multiple choice· CSEC Chemistry · May/June 2010 · Paper 1Which of the following can decolourize potassium manganate(VII)?
  63. Q71 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1The oxidation state of an ion of Element Z would MOST probably be
  64. Q231 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1Which of the compounds is reduced?
  65. Q241 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1Which of the compounds is the oxidising agent?
  66. Q251 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1Acidified potassium manganate (VII) is usually used as
  67. Q271 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1In which of the following does hydrogen have a negative oxidation number?
  68. Q371 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1The concentrated hydrochloric acid is acting as
  69. Q551 mark · multiple choice· CSEC Chemistry · May/June 2011 · Paper 1Which of the following processes CORRECTLY describes the reaction above?
  70. Q231 mark · multiple choice· CSEC Chemistry · May/June 2013 · Paper 1Item 23 refers to the following equation. \text{NO}_2(\text{g}) + \text{SO}_2(\text{g}) \rightarrow \text{NO}(\text{g}) + \text{SO}_3(\text{g}) Which of the following compounds is reduced?
  71. Q271 mark · multiple choice· CSEC Chemistry · May/June 2013 · Paper 1In which of the following reactions is sulfur dioxide acting as an oxidizing agent?
  72. Q81 mark · multiple choice· CSEC Chemistry · May/June 2015 · Paper 1An ion with a single negative charge may be converted into a neutral atom by
  73. Q221 mark · multiple choice· CSEC Chemistry · May/June 2015 · Paper 1In which of the following reactions is sulfur dioxide acting as an oxidizing agent?
  74. Q231 mark · multiple choice· CSEC Chemistry · May/June 2015 · Paper 1In which of the following compounds does hydrogen have a negative oxidation number?
  75. Q261 mark · multiple choice· CSEC Chemistry · May/June 2015 · Paper 1A solution, X, is added to acidified aqueous potassium iodide which turns brown. Addition of starch to the solution results in a dark blue colouration. It is possible that solution X contains
  76. Q241 mark · multiple choice· CSEC Chemistry · May/June 2016 · Paper 1The equation for the reaction of silicon with chlorine is \text{Si(s)} + 2\text{Cl}_2\text{(g)} \rightarrow \text{SiCl}_4(l). In this reaction, silicon is the reducing agent and is
  77. Q381 mark · multiple choice· CSEC Chemistry · May/June 2016 · Paper 1In which stage is the oxidation state of iron increased?
  78. Q491 mark · multiple choice· CSEC Chemistry · May/June 2017 · Paper 1A solution, when treated with sulfur dioxide gas, becomes green. The solution contains potassium

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