Oxidation-reduction is the process by which a material's surface reduces its own oxidation state, thereby reducing the rate of oxidation. By controlling a material's oxidation state, it can be forced to reduce pollutants such as NOx and VOCs. Oxidation-reduction is a key strategy in many pollution control technologies. In metals and other elements that are naturally oxidizing (like iron), oxides form on their surfaces and can react with other nearby molecules to form compounds that are more stable. These oxides can be dissolved in water to remove them from the environment, or they can be converted into less reactive compounds through electrolysis or other chemical processes.
Many polymers also reduce their oxidation state through chemical reactions when exposed to air or light. Oxidation-reduction has been used for centuries to purify water by removing impurities. Since then, it has been used in a wide range of products, from medical equipment and electronics to construction materials and vehicles.
In some cases, it is used for the purpose of reducing emissions, such as in catalytic converters. The potential for oxidation-reduction is huge, but there are many challenges to overcome before it can reach its full potential. One of the biggest issues is cost because most materials are too expensive to produce in large quantities using traditional manufacturing methods. To solve this problem, new manufacturing techniques and cheaper alternatives will be necessary.
Following are some of the multiple choice questions on the Oxidation Reduction with answers that will help the students in developing their knowledge.
Oxidation Reduction MCQ
1. What is the oxidation state of sulphur in SO42- (aq)?
2. Which of the following elements is the strongest oxidizing agent?
3. What is the oxidation number assigned to manganese in KMnO4?
4. In the reaction 2Ca(s) + O2(g) --> 2CaO(s), calcium is __________
5. In which substance does sulfur have a negative oxidation number?
6. What is the oxidation state of Nitrogen in N2 (g)?
7. Determine the oxidation number of chromium in CrO42-.
8. In a reaction, copper is reduced; its number of electrons has:
9. Which of these reagents can be used to convert Fe2+ to Fe3+ ion?I. Magnesium powderII. Potassium iodide solutionIII. Potassium hexacyanoferrate(II) solutionIV. Acidified potassium manganate(VII) solution
10. Which of the following statements is not true when zinc powder is added to dilute hydrochloric acid?
11. Which of the following reagents are able to change bromide ion in sodium bromide solution to bromine?I Sodium thiosulphate solutionII Acidified potassium dichromate(IV) solutionIII Acidified sodium chlorate(I) solutionIV Iodine solution
12. In the reaction Zn + H2O --> ZnO2 + H2 which element, if any, is oxidized?
13. A galvanic cell was created with a Calcium and a Copper cell. Which is the correct half equation at the anode?
14. Based on this equation: 2 I- + 2 Fe → 2Fe2+ + I2. Which of the following is true about the ionic equation?
15. Find the oxidation number of Ca in CaH2
16. Find the oxidation number of S in S2O4 2-
17. In an electrochemical cell, tin becomes a negative terminal when it is connected to
18. A mixture of magnesium oxide, copper(II) oxide and zinc powder is heated in a crucible until no further changes are observed. After heating, the mixture contains:
19. What substance is oxidized in the following reaction?4Fe + 3O2 --> 2Fe2O3
20. In a redox reaction, spectator ions...
21. If an atom loses electrons during a chemical reaction, the atom was:
22. Which of the following half reactions correctly represents a reduction half reaction?
23. Gaining oxygen is an example of...
24. Gaining hydrogen is an example of...
25. Oxidation is the _________ of electrons.
26. Another name for a "oxidation-reduction" reaction is
27. Substance that oxidizes another substance by accepting its electrons.
28. A decrease in oxidation number.
29. Which of the following is the balanced half -reaction for the oxidation of Cu to Cu+2?
30. The oxidation number of Hydrogen in KH potassium hydride equals:
31. An aqueous solution of potassium iodide turns from colourless to brown. What happens to the iodide ions?
32. What is the colour change of acidified KMnO4 solution when it is used as an oxidising agent?
33. What is the oxidation number of iodine in KIO3?
34. Reduction is the ___________ of electrons.
35. Which element was oxidized in the reaction below?Na + PbCl2 → Pb + NaCl
36. Which element was reduced in the reaction below?Na + PbCl2 → Pb + NaCl
37. An element's oxidation numbers became more negative during a reaction. What happened to that element?
38. An element's oxidation numbers changed from zero to +2 during a reaction. What happened to that element?
39. An element's oxidation numbers remain the same during a reaction. What happened to that element?
40. What is the oxidation number on the nitrogen in NO2-?
41. What is the oxidation number on the nitrogen in Mg3N2?
42. What is the oxidation number on the nitrogen in NO?
43. If an atom lost electrons, it...
44. Of the 5 types of reactions, which one(s) are oxidation-reduction?
45. Which of the following is NOT an example of an oxidation reduction reaction?
46. Which of the following has an oxidation number of zero on the chlorine atom?
47. If oxidation happened, then...
48. During the process of reduction, _________________
49. Which statement is true:Mg → Mg2+ + 2e–
50. In a redox reaction, the species reduced
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