This quiz works best with JavaScript enabled. Home > Cbse > Class 11 > Science > Chemistry Part Ii > Class 11 Chemistry (Part Ii) Chapter 8 Redox Reactions – Quiz 11 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 11 Chemistry (Part Ii) Chapter 8 Redox Reactions Quiz 11 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What is a half-reaction in redox chemistry? A) A reaction that occurs only in acidic solutions. B) A process that involves the complete reaction of a substance. C) A type of reaction that does not involve electron transfer. D) A half-reaction is either the oxidation or reduction part of a redox reaction, showing the transfer of electrons. Show Answer Correct Answer: D) A half-reaction is either the oxidation or reduction part of a redox reaction, showing the transfer of electrons. 2. Why are ionic equations useful? A) They show only the reacting ions. B) They simplify the reaction by including all ions. C) They highlight the role of spectator ions. D) They demonstrate the physical state of the reactants. Show Answer Correct Answer: A) They show only the reacting ions. 3. What are some applications of redox reactions in everyday life? A) Cooking food. B) Plant growth. C) Water purification. D) Applications of redox reactions include batteries, respiration, corrosion, and bleaching. Show Answer Correct Answer: D) Applications of redox reactions include batteries, respiration, corrosion, and bleaching. 4. KMnO4 + 4KOH $\rightarrow$ 4K$_{2}$MnO4 + 2H$_{2}$O + O$_{2}$change in oxidation number of Mn? A) 6. B) 1. C) 7. D) 2. Show Answer Correct Answer: B) 1. 5. In a redox reaction, the reducing agent will A) Lose an electron and be reduced. B) Lose an electron and be oxidized. C) Gain an electron and be reduced. D) Gain an electron and be oxidized. Show Answer Correct Answer: B) Lose an electron and be oxidized. 6. The reduction process involves A) Increase in oxidation number. B) Decrease in oxidation number. C) No change in oxidation number. D) Sometimes increase and sometimes decrease in oxidation number. Show Answer Correct Answer: B) Decrease in oxidation number. 7. In the electrolysis process of water ..... A) H$^{+}$ ions are reducing agent. B) Oxygen gas is collected at anode. C) OH$^{-}$ ions are reduced. D) H$^{+ }$ions are oxidized. Show Answer Correct Answer: B) Oxygen gas is collected at anode. 8. S in HSO$_{4}$$^{-}$? A) +2. B) -6. C) +5. D) +6. Show Answer Correct Answer: D) +6. 9. Which reaction shows the smallest change in the oxidation state of nitrogen? A) N$_{2}$(g) + 3H$_{2}$(g) $\rightarrow$ 2NH$_{3}$(g). B) 2NO(g) + O$_{2}$(g) $\rightarrow$ 2NO$_{2}$ (g). C) 2NH$_{3}$(g) + 3CuO(s)$\rightarrow$ N$_{2}$(g) + 3Cu(s) + 3H$_{2}$O(l)). D) 4NO$_{2}$(g) + O$_{2}$(g) + 2H$_{2}$O(l) $\rightarrow$ 4HNO$_{3}$(l). Show Answer Correct Answer: D) 4NO$_{2}$(g) + O$_{2}$(g) + 2H$_{2}$O(l) $\rightarrow$ 4HNO$_{3}$(l). 10. What are some common examples of redox reactions in everyday life? A) Common examples of redox reactions include combustion of fuels, cellular respiration, rusting of iron, photosynthesis, and batteries generating electricity. B) Boiling water. C) Melting of ice. D) Photosynthesis in animals. Show Answer Correct Answer: A) Common examples of redox reactions include combustion of fuels, cellular respiration, rusting of iron, photosynthesis, and batteries generating electricity. 11. Bordo mix that is used in agriculture cannot be held in an iron container because iron reacts with the copper (II) sulphate. In the reaction, iron A) Is an oxidising agent. B) Is a reducing agent. C) Is reduced. D) Has a decrease in oxidation number. Show Answer Correct Answer: B) Is a reducing agent. 12. What is the oxidation state of Cl in HClO$_{3}$? A) +5. B) +6. C) -6. D) -1. Show Answer Correct Answer: A) +5. 13. The sum of all oxidation numbers in a neutral compound is ..... A) 0. B) 1. C) -1. D) Depends on the compound. Show Answer Correct Answer: A) 0. 14. What is the species that lose electrons in a redox reaction? A) Is reduced. B) Reducing agent. C) Oxidizing agent. D) Decreases in oxidation number. Show Answer Correct Answer: B) Reducing agent. 15. Why is potassium nitrate classified as an electrolyte? A) It is a molecular compound. B) It releases ions in an aqueous solution. C) It contains a metal. D) It can conduct electricity as a solid. Show Answer Correct Answer: B) It releases ions in an aqueous solution. 16. What is the role of sulfuric acid in the titration of KMnO4? A) Sulfuric acid is used to increase the volume of the solution. B) Sulfuric acid acts as an acidifying agent to facilitate the reduction of KMnO4. C) Sulfuric acid neutralizes KMnO4 during the titration. D) Sulfuric acid acts as a catalyst for the reaction. Show Answer Correct Answer: B) Sulfuric acid acts as an acidifying agent to facilitate the reduction of KMnO4. 17. Which of the following statements is true for the reaction:@@ext{2H} ..... 2ext{O} ightarrow ext{2H} ..... 2 + ext{O} ..... 2@@? A) Water is reduced. B) Oxygen is reduced. C) Hydrogen is oxidized. D) Water is oxidized. Show Answer Correct Answer: D) Water is oxidized. 18. Oxygen always has an oxidation number of ..... A) 2. B) -2. C) -1. D) 1. Show Answer Correct Answer: B) -2. 19. What are the spectator ions in this reaction?CuCl$_{2}$(aq) $_{}$+ NaOH(aq) $\rightarrow$ Cu(OH)$_{2}$(s) + NaCl(aq) A) Cu$^{2+}$ and OH$^{1-}$. B) Na$^{2+}$ and Cl$^{2-}$. C) Na$^{1+}$ and Cl$^{1-}$. D) Na$^{1+}$ and OH$^{1-}$. Show Answer Correct Answer: C) Na$^{1+}$ and Cl$^{1-}$. 20. Which of the Cl species can never undergo disproportionation reaction? A) ClO$^{-3}$. B) ClO$^{-4}$. C) ClO$^{-2}$. D) ClO$^{-}$. Show Answer Correct Answer: B) ClO$^{-4}$. 21. Identify the species reduced in the following reaction.Fe$_{(s)}$ + 2 Ag$^{+}$$_{(aq) }$$\rightarrow$ Fe$^{2+}$$_{(aq)}$ + 2 Ag$_{(s)}$ A) Fe. B) Ag. C) None of these. D) None of the above. Show Answer Correct Answer: B) Ag. 22. A substance that oxidizes another substance by accepting its electrons is called an ..... A) Reducing agent. B) Oxidation number. C) Oxidizing agent. D) None of the above. Show Answer Correct Answer: C) Oxidizing agent. 23. What element is being reduced?I$_{2}$ + H$_{2}$SO$_{3}$ + H$_{2}$O $\rightarrow$ 2 HI + H$_{2}$SO$_{4}$ A) O. B) I. C) S. D) H. Show Answer Correct Answer: B) I. 24. Which of the following half reactions correctly represents a reduction half reaction? A) Pb$^{4+}$ + 2e$^{-}$ $\rightarrow$Pb$^{2+}$. B) Fe $\rightarrow$Fe$^{2+ }$+ 2e$^{-}$. C) Fe + 3e$^{-}$ $\rightarrow$Fe$^{3+}$. D) 2O$^{-2 }$$\rightarrow$O$_{2}$ + 4e$^{-}$. Show Answer Correct Answer: A) Pb$^{4+}$ + 2e$^{-}$ $\rightarrow$Pb$^{2+}$. 25. What particles are transferred in an oxidation-reduction reaction? A) Protons. B) Atoms. C) Ions. D) Electrons. Show Answer Correct Answer: D) Electrons. 26. Why are porous electrodes important in fuel cells? A) To decrease the overall weight of the cell. B) To increase the surface area for reaction, thereby enhancing efficiency. C) To make the cell look aesthetically pleasing. D) To reduce the cost of fuel cell production. Show Answer Correct Answer: B) To increase the surface area for reaction, thereby enhancing efficiency. 27. Which of the following is a characteristic of a reduction process? A) Loss of protons. B) Gain of protons. C) Gain of electrons. D) Loss of electrons. Show Answer Correct Answer: C) Gain of electrons. 28. Which equation represents a redox reaction? A) NaOH + HNO$_{3 }$$\rightarrow$ NaNO$_{3}$ +H$_{2}$O. B) CaCO$_{3}$ + 2HCl $\rightarrow$ CaCl$_{2}$ + H$_{2}$O + CO$_{2}$. C) 2NaCl + Pb(NO$_{3}$)$_{2}$ $\rightarrow$ PbCl$_{2}$ + 2NaNO$_{3}$. D) 2AgNO$_{3}$ + Zn $\rightarrow$ Zn(NO$_{3}$)$_{2}$ + 2Ag. Show Answer Correct Answer: D) 2AgNO$_{3}$ + Zn $\rightarrow$ Zn(NO$_{3}$)$_{2}$ + 2Ag. 29. In the half-reaction $MnO_4^-\rightarrow Mn^{2+}$ A) +7 to +2. B) +2 to +7. C) +4 to +2. D) +2 to +4. Show Answer Correct Answer: A) +7 to +2. 30. Which of the following is used in the breathalyzer test to detect the presence of alcohol? A) Lime water. B) Bromine water. C) Potassium dichromate. D) Lighter splint. Show Answer Correct Answer: C) Potassium dichromate. 31. Why does aluminium tend not to corrode as much as iron when it is exposed to moist air? A) Energy must be added to cause aluminium to corrode. B) A layer of aluminium oxide protects the metal beneath. C) Aluminium does not lose electrons easily. D) Aluminium does not react with oxygen unless salt is present. Show Answer Correct Answer: B) A layer of aluminium oxide protects the metal beneath. 32. The iron (II) ion, Fe$^{2+}$(aq) A) Can act as an oxidant but not a reductant. B) Can oxidise solid zinc and reduce liquid bromine. C) Can act as a reductant but not an oxidant. D) Will always be reduced to Fe(s) in redox reactions. Show Answer Correct Answer: B) Can oxidise solid zinc and reduce liquid bromine. 33. What is the easier technique for balancing redox reactions under basic conditions? A) Use the neutralization method. B) Start with acidic conditions and then add hydroxide. C) Start with basic conditions and then add acid. D) Use the full reaction method. Show Answer Correct Answer: B) Start with acidic conditions and then add hydroxide. 34. The third step in balancing the redox reaction using oxidation-number-change is A) Check the balancing for both atoms and charge. B) Use coefficients to make the total increase in oxidation number equal to the total decrease in oxidation number. C) Assign oxidation numbers to each of the atoms in the equation and write the numbers above the atom. D) Use a line to connect the atoms that are undergoing a change in oxidation number. Show Answer Correct Answer: D) Use a line to connect the atoms that are undergoing a change in oxidation number. 35. What ions are present in molten aluminium oxide? A) Al$^{3+}$, O$^{2-}$, H$^{+}$, OH$^{-}$. B) Al$^{3+}$, O$^{2-}$. C) Al$^{3+}$, OH$^{-}$. D) None of the above. Show Answer Correct Answer: B) Al$^{3+}$, O$^{2-}$. 36. When a reactant loses hydrogen ..... A) Oxidation reaction occur. B) Reduction reaction occur. C) Combustion occur. D) Hydrogenation occur. Show Answer Correct Answer: A) Oxidation reaction occur. 37. Why is it important to balance both particles and charges in a redox reaction? A) To ensure conservation of charge. B) To speed up the reaction. C) To simplify the equation. D) To ensure conservation of mass. Show Answer Correct Answer: A) To ensure conservation of charge. 38. The ability of an atom to attract the bonding electrons to itself is defined as ..... A) Ionic bond. B) Ionization energy. C) Electron affinity. D) Electronegativity. Show Answer Correct Answer: D) Electronegativity. 39. How do you balance a half equation for a reaction? A) By changing the charge of ions. B) By adding or removing electrons to balance charge. C) By adding spectator ions. D) By adding or removing protons. Show Answer Correct Answer: B) By adding or removing electrons to balance charge. 40. $\Delta$H = + 300 kJ A) Endo. B) Exo. C) All the above. D) None of the above. Show Answer Correct Answer: A) Endo. 41. What is the role of hydrogen ions in the reaction with magnesium? A) They precipitate out as a solid. B) They gain electrons and form hydrogen gas. C) They act as spectator ions. D) They lose electrons and form hydrogen gas. Show Answer Correct Answer: B) They gain electrons and form hydrogen gas. 42. What role do oxidation states play in chemistry? A) They determine the color of compounds. B) They simplify the tracking of electron sharing. C) They indicate the temperature of a reaction. D) They measure the acidity of a solution. Show Answer Correct Answer: B) They simplify the tracking of electron sharing. 43. Which of the following is the balanced half-reaction for the oxidation of Cu to Cu$^{+2?}$ A) Cu $\rightarrow$ Cu$^{+2 }$+ 2 e-. B) Cu $\rightarrow$ Cu$^{+2}$. C) Cu-2e-$\rightarrow$ Cu$^{+2}$. D) Cu + 2 e-$\rightarrow$ Cu$^{+2}$. Show Answer Correct Answer: A) Cu $\rightarrow$ Cu$^{+2 }$+ 2 e-. 44. What is the oxidation state of carbon in the reaction with silver diamine? A) +2. B) +4. C) +3. D) +1. Show Answer Correct Answer: B) +4. 45. The last step in balancing the redox reaction using oxidation-number change method is check the balancing for both atoms and charge. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 46. How many electrons are transferred in the reaction below?4Fe + 3O$_{2}$ $\rightarrow$ 2Fe$_{2}$O$_{3}$ A) 4 electrons. B) 3 electrons. C) 6 electrons. D) 12 electrons. Show Answer Correct Answer: D) 12 electrons. 47. What is the oxidation number of Chlorine in HClO4? A) +7. B) +5. C) +1. D) +3. Show Answer Correct Answer: A) +7. 48. In the reaction of hydrogen with iodine, which is the reducing agent? A) Iodine. B) Hydrogen ion. C) Hydrogen. D) Iodide ion. Show Answer Correct Answer: C) Hydrogen. 49. Explain the role of a salt bridge in an electrochemical cell. A) The role of a salt bridge in an electrochemical cell is to maintain electrical neutrality and allow ion flow between the half-cells. B) To increase the voltage of the cell. C) To prevent the flow of electrons. D) To act as a catalyst in the reaction. Show Answer Correct Answer: A) The role of a salt bridge in an electrochemical cell is to maintain electrical neutrality and allow ion flow between the half-cells. 50. In electrolytic cell which its electrolyte is aqueous copper (II) sulfate, copper are used as electrodes. What is the product at the anode? A) Oxygen gas and water. B) Copper metal. C) Copper (II) ions. D) Hydrogen gas. Show Answer Correct Answer: C) Copper (II) ions. 51. What is oxidation number of O$_{2}$? A) +2. B) +1. C) 0. D) -2. Show Answer Correct Answer: C) 0. 52. What happens to the oxidation number of an element during oxidation? A) The oxidation number of an element increases. B) The oxidation number of an element remains the same. C) The oxidation number of an element fluctuates. D) The oxidation number of an element decreases. Show Answer Correct Answer: A) The oxidation number of an element increases. 53. Reducing agents are the substances that oxidises another substances ..... A) False. B) True. C) All the above. D) None of the above. Show Answer Correct Answer: A) False. 54. Hydrogen peroxide is not a reducing agent. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: B) False. 55. How does the Haber process impact society? A) By generating renewable energy. B) By producing clean water. C) By reducing air pollution. D) By feeding billions with fertilizer. Show Answer Correct Answer: D) By feeding billions with fertilizer. 56. Oxidation happens at the A) Anode. B) Voltmeter. C) Cathode. D) Salt bridge. Show Answer Correct Answer: A) Anode. 57. What is the reduction half-reaction for the following redox reaction? Zn + HgO $\longrightarrow$ A) ZnO + Hg. B) Zn + HgO. C) Hg2+ + 2e-$\longrightarrow$. D) Zn $\longrightarrow$. Show Answer Correct Answer: C) Hg2+ + 2e-$\longrightarrow$. 58. Which of the following would oxidize an aldehyde to a carboxylic acid? A) $KMnO_4$. B) PCC. C) $OsO_4$. D) $O_3$ $\left(CH_3\right)_2S$. Show Answer Correct Answer: A) $KMnO_4$. 59. Which is the correct net ionic equation for the reaction of AgNO$_{3}$ and CaCl$_{2}$? A) Ag + Cl $\rightarrow$ AgCl. B) Ca$^{2+}$(aq) + 2Cl$^{-}$ (aq) $\rightarrow$ CaCl(s). C) Ag$^{+}$(aq) + Cl$^{-}$ (aq) $\rightarrow$ AgCl(s). D) Ag$^{+ }$+ Ca$^{2}$$^{+}$ $\rightarrow$Ag$_{2}$Ca (s). Show Answer Correct Answer: C) Ag$^{+}$(aq) + Cl$^{-}$ (aq) $\rightarrow$ AgCl(s). 60. Which statement about redox reactions is FALSE? A) Oxidation and reduction always occur together. B) Oxidation involves loss of electrons. C) The oxidizing agent is always reduced. D) The reducing agent is oxidized and gains electrons. Show Answer Correct Answer: D) The reducing agent is oxidized and gains electrons. ← PreviousNext →Related QuizzesScience QuizzesClass 11 QuizzesClass 11 Chemistry (Part Ii) Chapter 8 Redox Reactions Quiz 1Class 11 Chemistry (Part Ii) Chapter 8 Redox Reactions Quiz 2Class 11 Chemistry (Part Ii) Chapter 8 Redox Reactions Quiz 3Class 11 Chemistry (Part Ii) Chapter 8 Redox Reactions Quiz 4Class 11 Chemistry (Part Ii) Chapter 8 Redox Reactions Quiz 5Class 11 Chemistry (Part Ii) Chapter 8 Redox Reactions Quiz 6Class 11 Chemistry (Part Ii) Chapter 8 Redox Reactions Quiz 7Class 11 Chemistry (Part Ii) Chapter 8 Redox Reactions Quiz 8 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books