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 9 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 11 Chemistry (Part Ii) Chapter 8 Redox Reactions Quiz 9 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. In a voltaic cell electrons flow A) Through the salt bridge. B) From the cathode to the anode through the wire. C) From the anode to the cathode through the wire. D) None of the above. Show Answer Correct Answer: C) From the anode to the cathode through the wire. 2. What is the role of inert electrodes in a galvanic cell? A) To participate actively in the chemical reaction and get consumed. B) To provide a surface for the redox reaction without undergoing any chemical change themselves. C) To increase the electrical resistance of the cell. D) To act as a source of ions in the electrolyte solution. Show Answer Correct Answer: B) To provide a surface for the redox reaction without undergoing any chemical change themselves. 3. In the reaction 2Ca(s) + O$_{2}$(g) $\rightarrow$ 2CaO(s), calcium is ..... A) Reduced. B) Synthesized. C) Oxidized. D) None of the above. Show Answer Correct Answer: C) Oxidized. 4. Which of the following metals will not corrode easily? A) Gold. B) Zinc. C) Iron. D) Aluminium. Show Answer Correct Answer: A) Gold. 5. The species that loses electron is ..... and usually ..... agent. A) Oxidized;reducing. B) Reduced;oxidizing. C) Reduced;reducing. D) Oxidized;oxidizing. Show Answer Correct Answer: A) Oxidized;reducing. 6. Calculate the standard cell potential for the reaction:$Zn + Cu^{2+} \rightarrow Zn^{2+} + Cu$ $E^\circ_{Zn^{2+}/Zn} =-0.76 \, V$ $E^\circ_{Cu^{2+}/Cu} = +0.34 \, V$ A) +1.10 V. B) -0.42 V. C) -1.10 V. D) +0.42 V. Show Answer Correct Answer: A) +1.10 V. 7. Which type of reaction is the conversion of iron oxide to iron and oxygen? A) Reduction. B) Oxidation. C) Neutralisation. D) Combination. Show Answer Correct Answer: A) Reduction. 8. In order to be considered an oxidation-reduction reaction, A) A precipitate must form. B) The oxidation number of two species must change. C) The pH must change. D) None of the above. Show Answer Correct Answer: B) The oxidation number of two species must change. 9. Which example shows combination reaction? A) 2NaH $\rightarrow$ 2Na + H$_{2}$. B) 4Fe+ 3O$_{2}$$\rightarrow$2Fe$_{2}$O$_{3}$. C) P$_{4}$ + 3NaOH + 3H$_{2}$O $\rightarrow$ 3NaH$_{2}$PO$_{2}$ + PH$_{3}$. D) None of the above. Show Answer Correct Answer: B) 4Fe+ 3O$_{2}$$\rightarrow$2Fe$_{2}$O$_{3}$. 10. What element always has an oxidation number of-1? A) Fluorine. B) Iodine. C) Chlorine. D) Hydrogen. Show Answer Correct Answer: A) Fluorine. 11. What is the most important type of reaction in chemistry involving electron transfer? A) Acid base reactions. B) Covalent bond reactions. C) Ionic bond reactions. D) Redox reactions. Show Answer Correct Answer: D) Redox reactions. 12. Which element is reduced in the following reaction?2K$_{2}$Cr$_{2}$O$_{7}$ + 2H$_{2}$O + 3S $\rightarrow$ 3SO$_{2}$ + 4KOH + 2Cr$_{2}$O$_{3}$ A) Cr. B) O. C) K. D) S. Show Answer Correct Answer: D) S. 13. Which is not a redox reaction? A) Corrosion (rusting). B) Cellular respiration. C) Baking a cake. D) Apple turning brown. Show Answer Correct Answer: C) Baking a cake. 14. What is lost or gained in a redox reaction? A) Electrons. B) Ions. C) Atoms. D) Protons. Show Answer Correct Answer: A) Electrons. 15. Which of the following is an oxidation process? A) A chlorine molecule gains hydrogen. B) A sodium atom loses an electron. C) A bromine atom gains an electron. D) Carbon dioxide loses oxygen. Show Answer Correct Answer: B) A sodium atom loses an electron. 16. For lithium-ion batteries ..... A) Electrons flow from lithium to graphite. B) Graphite is the cathode. C) Electrons flow from graphite to lithium. D) Lithium is the anode. Show Answer Correct Answer: C) Electrons flow from graphite to lithium. 17. Which of the following is the formula of Tin(IV) oxide? A) TiO$_{4}$. B) SnO$_{2}$. C) SnO$_{4}$. D) TiO$_{2}$. Show Answer Correct Answer: B) SnO$_{2}$. 18. What is the oxidation number of phosphorus in H3PO4? A) +3. B) +1. C) +5. D) 0. Show Answer Correct Answer: C) +5. 19. What is the relationship between redox reactions and electrochemistry? A) Redox reactions only occur in non-aqueous solutions. B) Redox reactions are fundamental to electrochemistry as they involve electron transfer, which is the basis for generating or using electrical energy. C) Electrochemistry is unrelated to chemical reactions. D) Redox reactions do not involve electron transfer. Show Answer Correct Answer: B) Redox reactions are fundamental to electrochemistry as they involve electron transfer, which is the basis for generating or using electrical energy. 20. What is the position of hydrogen ion in the electrochemical series? A) Between lead (II) ion and iron (III) ion. B) Between zinc iron and iron (II) ion. C) Between lead (II) ion and copper (II) ion. D) Between zinc ion and tin (II) ion. Show Answer Correct Answer: C) Between lead (II) ion and copper (II) ion. 21. Which of the following pairs is an example of conjugate redox pairs? A) $H_2O/O_2$. B) $Fe^{2+}/Fe^{3+}$. C) $Cl_2/Cl^-$. D) $Na/Na^+$. Show Answer Correct Answer: B) $Fe^{2+}/Fe^{3+}$. 22. Which of the following is NOT a characteristic of redox reactions? A) They follow the law of conservation of charge (mass). B) They always occur in aqueous solutions. C) They can be split into half-reactions. D) They involve electron transfer. Show Answer Correct Answer: B) They always occur in aqueous solutions. 23. What is the primary characteristic of redox reactions? A) They do not involve electron transfer. B) They involve both oxidation and reduction. C) They involve only reduction. D) They involve only oxidation. Show Answer Correct Answer: B) They involve both oxidation and reduction. 24. Name the oxidising agent in the following reaction:nitrogen + hydrogen $\rightarrow$ ammoniaN2 + 3 H2 ..... 2 NH3 A) Nitrogen. B) Hydrogen. C) Ammonia. D) None of the above. Show Answer Correct Answer: A) Nitrogen. 25. Consider the following REDOX reaction:Cl$_{2}$(g) $\rightarrow$ ClO$^{-}$(aq) + Cl$^{-}$(aq) (basic solution)Which species is the result of oxidation? A) Cl$^{-}$. B) ClO$^{-}$. C) All the above. D) None of the above. Show Answer Correct Answer: B) ClO$^{-}$. 26. A chemical reaction that involves a gain/loss of electrons is called: A) Dehydration reaction. B) Oxidation-Reduction. C) Hydrolysis. D) Respiration. Show Answer Correct Answer: B) Oxidation-Reduction. 27. How is a reduction half reaction identified? A) Protons on the left side. B) Electrons on the left side. C) Electrons on the right side. D) No electrons present. Show Answer Correct Answer: B) Electrons on the left side. 28. Which is a difference between electrolytic and voltaic cells? A) Reduction occurs at the anode in electrolysis. B) Electrolysis reactions are spontaneous. C) Oxidation occurs at the negative electrode in electrolysis. D) The cathode is negative in electrolysis. Show Answer Correct Answer: D) The cathode is negative in electrolysis. 29. What happens during oxidation? A) A substance gains hydrogen. B) A substance loses hydrogen. C) A substance gains electrons. D) A substance loses electrons. Show Answer Correct Answer: D) A substance loses electrons. 30. In the reaction Zn + H$_{2}$O $\rightarrow$ ZnO$_{2}$ + H$_{2}$ which element is oxidized? A) Zinc. B) Hydrogen. C) Oxygen. D) None. Show Answer Correct Answer: A) Zinc. 31. What are the spectator ions in the reaction of sodium chloride with silver nitrate? A) Silver and nitrate. B) Sodium and chloride. C) Sodium and nitrate. D) Silver and chloride. Show Answer Correct Answer: C) Sodium and nitrate. 32. What type of reaction is this:SF$_{4 }$becomes SF$_{6}$ A) Hydrogenation. B) Reduction. C) Oxidation. D) None of the above. Show Answer Correct Answer: C) Oxidation. 33. What is the role of electrons in chemistry? A) All of the above. B) To bond atoms. C) To create energy. D) To form molecules. Show Answer Correct Answer: A) All of the above. 34. Which statement is true for a spontaneous redox reaction carried out at standard-state conditions? A) E$^\circ$$_{cell}$ is always positive. B) E$^\circ$$_{red}$ is always positive. C) E$^\circ$$_{ox}$ is always positive. D) E$^\circ$$_{red}$ is always negative. Show Answer Correct Answer: A) E$^\circ$$_{cell}$ is always positive. 35. What is the oxidation number for P in H$_{3}$PO$_{4}$? A) 3. B) 6. C) 5. D) 4. Show Answer Correct Answer: C) 5. 36. What is a half-reaction of this equation, Na + Cl $\rightarrow$ NaCl? A) Na $\rightarrow$ Na + e$^{-}$. B) Cl-e$^{-}$ $\rightarrow$ Cl$^{-}$. C) Na$^\circ$ + Cl$^\circ$$\rightarrow$ Na$^{+1}$Cl$^{-1}$. D) Cl + e$^{-}$ $\rightarrow$ Cl$^{-}$. Show Answer Correct Answer: D) Cl + e$^{-}$ $\rightarrow$ Cl$^{-}$. 37. What is the reducing agent of this reaction?2Al (s) + 6H$^{+ }$(aq)$_{ }$$\rightarrow$ 2Al$^{3+}$$_{ }$(aq) + 3H$_{2 }$(g) A) Al$^{3+}$. B) H$_{2}$. C) Al. D) H$^{+}$. Show Answer Correct Answer: C) Al. 38. Which formula contains nitrogen with an oxidation state of +3? A) KNO$_{2}$. B) NO$_{2}$. C) HNO$_{3}$. D) NH$_{3}$. Show Answer Correct Answer: A) KNO$_{2}$. 39. Oxidation involves A) Losing electrons; losing oxygen. B) Gaining electrons; losing oxygen. C) Gaining electrons; gaining oxygen. D) Losing electrons; gaining oxygen. Show Answer Correct Answer: D) Losing electrons; gaining oxygen. 40. How can the voltage of a galvanic cell be increased? A) By reversing the direction of electron flow. B) By connecting cells in series. C) By using a larger salt bridge. D) By decreasing the concentration of the electrolyte. Show Answer Correct Answer: B) By connecting cells in series. 41. Name one application of redox reactions in everyday life. A) Rusting of iron. B) Batteries. C) Photosynthesis. D) Combustion of fuels. Show Answer Correct Answer: B) Batteries. 42. KMnO$_{4}$ is strong oxidising agent in acid medium. To provide acid medium, H$_{2}$SO$_{4}$ is used instead of HCl because: A) H$_{2}$SO$_{4 }$is dibasic acid. B) Rate is faster in the presence of H$_{2}$SO$_{4}$. C) HCl is oxidised to Cl$_{2}$ by KMnO4. D) H$_{2}$SO$_{4 }$is stronger acid than HCl. Show Answer Correct Answer: C) HCl is oxidised to Cl$_{2}$ by KMnO4. 43. If HCl changes to chlorine gas it is A) Reduction. B) Oxidation. C) None of the above. D) Insufficient information. Show Answer Correct Answer: B) Oxidation. 44. E$^{0}$ values of some redox couples are given below. On the basis of these values choose the correct option.E$^{0 }$values:Br/Br$^{-}$ = + 1.90; Ag$^{+}$/Ag(s)=0.80 Cu$^{2+}$/Cu(s) = + 0.34; I$^{2}$ (s)/I$^{-}$ =+0.54 A) Cu will reduce Ag. B) Cu will reduce Br$^{-}$. C) Cu will reduce Br$_{2}$. D) Cu will reduce I$^{-}$. Show Answer Correct Answer: C) Cu will reduce Br$_{2}$. 45. Give the oxidation numbers of all the elements in the following molecules and ions:K2CrO4 A) +1, +7, +2. B) -2, +2, -7. C) -1, -7, +2. D) +1, +7, -2. Show Answer Correct Answer: D) +1, +7, -2. 46. Which gas is the strongest reducing agent? A) Cl$^{-}$. B) F$^{-}$. C) Br$^{-}$. D) I$^{-}$. Show Answer Correct Answer: B) F$^{-}$. 47. In a voltaic cell the ions flow through the A) Wire. B) Salt bridge. C) All the above. D) None of the above. Show Answer Correct Answer: B) Salt bridge. 48. Which of the following is not true of the Winkler method? A) BOD measures pollution. B) Iodine is oxidized in the process. C) It measures dissolved oxygen. D) It uses a titration with potassium permanganate. Show Answer Correct Answer: D) It uses a titration with potassium permanganate. 49. What is the oxidation state of iron in Fe$_{3}$O$_{4}$? A) -1. B) +3. C) 0. D) +2. Show Answer Correct Answer: B) +3. 50. The standard cell potential for the voltaic cell based on the reaction below is ..... V.Sn$^{2+ }$(aq) + 2 Fe$^{3+ }$(aq) $\rightarrow$ 2 Fe$^{2+ }$(aq) + Sn$^{4+ }$(aq) A) +0.46. B) +1.39. C) -0.46. D) +1.21. E) +0.617. Show Answer Correct Answer: E) +0.617. 51. Identify the type of the following redox reaction. CH$_{4}$ + 2O$_{2}$$\rightarrow$CO$_{2}$ + 2H$_{2}$O. A) Decomposition. B) Combination. C) Displacement. D) Disproportionation. Show Answer Correct Answer: C) Displacement. 52. What is the oxidation state of oxygen in most compounds? A) 0. B) +1. C) -1. D) -2. Show Answer Correct Answer: D) -2. 53. How do you determine if a reaction is spontaneous based on redox principles? A) A redox reaction is spontaneous if the reactants are in solid form. B) A redox reaction is spontaneous if the temperature is above 100$^\circ$C. C) A redox reaction is spontaneous if the reaction occurs in a closed container. D) A redox reaction is spontaneous if the standard cell potential (E$^\circ$) is positive. Show Answer Correct Answer: D) A redox reaction is spontaneous if the standard cell potential (E$^\circ$) is positive. 54. What is the oxidation number of chlorine in $ClO_3^-$ A) +3. B) +1. C) +7. D) +5. Show Answer Correct Answer: C) +7. 55. What type of reaction is the following? Zn$_{(s)}$ + 2Cu(NO$_{3}$)$_{2(aq) }$$\rightarrow$ 2Cu$_{(s)}$ + Zn(NO$_{3}$)$_{2(aq)}$ A) Single displacement. B) Neutralization. C) Double displacement. D) Precipitation. Show Answer Correct Answer: A) Single displacement. 56. What does it mean if a substance is oxidized? A) It means it has gained electrons and its oxidation state has decreased. B) It means it has lost electrons and its oxidation state has increased. C) It means it has remained unchanged in terms of electrons and oxidation state. D) It means it has combined with oxygen and formed a new compound. Show Answer Correct Answer: B) It means it has lost electrons and its oxidation state has increased. 57. Find oxidation states of sulfur in hydrosulfuric acid H2S A) +2. B) -2. C) -3. D) -1. Show Answer Correct Answer: B) -2. 58. Complete the general equation:Metal + Acid $\rightarrow$ A) Salt + Water. B) Salt + Hydrogen. C) Salt. D) None of the above. Show Answer Correct Answer: B) Salt + Hydrogen. 59. What occurs at the cathode in an electrolytic cell? A) Oxidation. B) Reduction. C) All the above. D) None of the above. Show Answer Correct Answer: B) Reduction. 60. Which of the following unbalanced equations represents oxidation? A) Cl$_{2}$ $\rightarrow$ 2Cl$^{-}$. B) Fe$^{3+}$ $\rightarrow$ Fe$^{2+}$. C) Zn $\rightarrow$ Zn$^{2+}$. D) C + H2 $\rightarrow$ CH$_{4}$. Show Answer Correct Answer: C) Zn $\rightarrow$ Zn$^{2+}$. ← 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