CBSE Class 11 The Redox Reaction MCQ

Understanding redox reactions is a fundamental part of the Class 11 Chemistry curriculum. Redox reactions, short for reduction-oxidation reactions, involve the transfer of electrons between two substances. They are pivotal in both organic and inorganic chemistry and are directly linked to concepts such as electron transfer, oxidation states, and the identification of reducing and oxidizing agents. To help students reinforce their understanding and assess their knowledge, multiple-choice questions (MCQs) are an excellent tool.

This collection of Redox Reaction MCQ Class 11 with Answers is designed to provide a comprehensive overview of the topic, offering students the opportunity to practice and test their grasp of redox reactions. Each question is carefully crafted to challenge students’ understanding while helping them to prepare effectively for their exams. The answers are included to ensure immediate feedback, enabling learners to identify areas that require further study.

For those looking to delve deeper or use these resources for revision, a Redox Reaction Class 11 MCQ PDF can be particularly useful. It provides a printable format that students can use for offline study. This collection is not only a valuable resource for self-assessment but also serves as a vital tool for teachers who wish to provide additional support through practice questions. As students work through these Redox Reaction MCQ with Answers, they will enhance their problem-solving skills and deepen their comprehension of this crucial chemical process.

CBSE Class 11 Chemistry Redox Reaction with Answers

Concept-Based Questions

1. Redox reactions involve:
   a) Transfer of protons
   b) Transfer of neutrons
   c) Transfer of electrons
   d) None of these
   Answer: c) Transfer of electrons
2. Oxidation is defined as:
   a) Gain of electrons
   b) Loss of electrons
   c) Gain of protons
   d) None of these
   Answer: b) Loss of electrons
3. Reduction is defined as:
   a) Gain of electrons
   b) Loss of protons
   c) Loss of electrons
   d) Gain of neutrons
   Answer: a) Gain of electrons
4. In a redox reaction, the substance that undergoes oxidation is called:
   a) Oxidizing agent
   b) Reducing agent
   c) Catalyst
   d) Inert element
   Answer: b) Reducing agent
5. In a redox reaction, the substance that undergoes reduction is called:
   a) Oxidizing agent
   b) Reducing agent
   c) Catalyst
   d) Oxide
   Answer: a) Oxidizing agent

Oxidation Number

1. Oxidation number of oxygen in H₂O₂ is:
   a) –2
   b) –1
   c) 0
   d) +1
   Answer: b) –1
2. Oxidation number of chlorine in NaClO₃ is:
   a) +1
   b) +3
   c) +5
   d) –1
   Answer: c) +5
3. Oxidation number of Mn in KMnO₄ is:
   a) +2
   b) +4
   c) +6
   d) +7
   Answer: d) +7
4. Oxidation number of nitrogen in NH₄⁺ is:
   a) –3
   b) –2
   c) –1
   d) 0
   Answer: a) –3
5. Oxidation number of S in H₂SO₄ is:
   a) +2
   b) +4
   c) +6
   d) –2
   Answer: c) +6
6. Types of Redox Reactions
   Which of the following is a disproportionation reaction?
   a) 2H₂ + O₂ → 2H₂O
   b) 2KClO₃ → 2KCl + 3O₂
   c) Cl₂ + H₂O → HCl + HOCl
   d) CuO + H₂ → Cu + H₂O
   Answer: c) Cl₂ + H₂O → HCl + HOCl
7. Which reaction is an example of oxidation?
   a) Zn → Zn²⁺ + 2e⁻
   b) Cu²⁺ + 2e⁻ → Cu
   c) H₂ + Cl₂ → 2HCl
   d) NH₃ + HCl → NH₄Cl
   Answer: a) Zn → Zn²⁺ + 2e⁻
8. Which reaction represents reduction?
   a) Fe²⁺ → Fe³⁺ + e⁻
   b) Cu²⁺ + 2e⁻ → Cu
   c) 2Na → 2Na⁺ + 2e⁻
   d) H₂ → 2H⁺ + 2e⁻
   Answer: b) Cu²⁺ + 2e⁻ → Cu
9. Which reaction is a combination redox reaction?
   a) N₂ + 3H₂ → 2NH₃
   b) 2HgO → 2Hg + O₂
   c) Zn + CuSO₄ → ZnSO₄ + Cu
   d) H₂O₂ → H₂O + O₂
   Answer: a) N₂ + 3H₂ → 2NH₃
10. Which reaction is a decomposition redox reaction?
    a) Zn + H₂SO₄ → ZnSO₄ + H₂
    b) 2KClO₃ → 2KCl + 3O₂
    c) NaOH + HCl → NaCl + H₂O
    d) Cu + Cl₂ → CuCl₂
    Answer: b) 2KClO₃ → 2KCl + 3O₂
11. Examples & Applications
    Oxidation number of Cr in K₂Cr₂O₇ is:
    a) +3
    b) +6
    c) +2
    d) +7
    Answer: b) +6
12. Oxidation number of Fe in Fe(CO)₅ is:
    a) 0
    b) +2
    c) +3
    d) +5
    Answer: a) 0
13. In the reaction: Zn + CuSO₄ → ZnSO₄ + Cu, which is reduced?
    a) Zn
    b) Cu²⁺
    c) SO₄²⁻
    d) None
    Answer: b) Cu²⁺
14. Which of the following is not a redox reaction?
    a) NaOH + HCl → NaCl + H₂O
    b) 2Mg + O₂ → 2MgO
    c) Zn + 2HCl → ZnCl₂ + H₂
    d) Cu + Cl₂ → CuCl₂
    Answer: a) NaOH + HCl → NaCl + H₂O
15. Which of the following is an oxidizing agent?
    a) H₂
    b) Na
    c) O₂
    d) H₂O
    Answer: c) O₂
16. Electrochemistry Angle
    In Daniell cell, which electrode acts as anode?
    a) Cu
    b) Zn
    c) Both
    d) None
    Answer: b) Zn
17. In a galvanic cell, oxidation occurs at:
    a) Cathode
    b) Anode
    c) Both electrodes
    d) Electrolyte
    Answer: b) Anode
18. In a galvanic cell, reduction occurs at:
    a) Cathode
    b) Anode
    c) Both electrodes
    d) Electrolyte
    Answer: a) Cathode
19. In Zn + Cu²⁺ → Zn²⁺ + Cu, Zn acts as:
    a) Oxidizing agent
    b) Reducing agent
    c) Both
    d) None
    Answer: b) Reducing agent
20. In Zn + Cu²⁺ → Zn²⁺ + Cu, Cu²⁺ acts as:
    a) Oxidizing agent
    b) Reducing agent
    c) Catalyst
    d) Inert electrode
    Answer: a) Oxidizing agent

Numerical / Conceptual

1. Equivalent mass of KMnO₄ in acidic medium is:
   a) M/1
   b) M/2
   c) M/3
   d) M/5
   Answer: d) M/5
2. Oxidation number of chlorine in ClO₂ is:
   a) +1
   b) +2
   c) +3
   d) +4
   Answer: d) +4
3. Oxidation number of phosphorus in H₃PO₄ is:
   a) +3
   b) +4
   c) +5
   d) +6
   Answer: c) +5
4. Oxidation number of chlorine in NaClO is:
   a) –1
   b) +1
   c) +3
   d) +5
   Answer: b) +1
5. Which is the correct representation of oxidation?
   a) Fe³⁺ → Fe²⁺ + e⁻
   b) Zn → Zn²⁺ + 2e⁻
   c) Cl₂ + 2e⁻ → 2Cl⁻
   d) Cu²⁺ + 2e⁻ → Cu
   Answer: b) Zn → Zn²⁺ + 2e⁻
6. Conceptual (Advanced)
   In H₂ + Cl₂ → 2HCl, H₂ is:
   a) Oxidized
   b) Reduced
   c) Oxidizing agent
   d) Catalyst
   Answer: a) Oxidized
7. In H₂ + Cl₂ → 2HCl, Cl₂ is:
   a) Reduced
   b) Oxidized
   c) Reducing agent
   d) Inert
   Answer: a) Reduced
8. Which of the following cannot act as both oxidizing and reducing agent?
   a) H₂O₂
   b) O₃
   c) H₂SO₄ (conc.)
   d) F₂
   Answer: d) F₂
9. Which is not a redox reaction?
   a) CaCO₃ → CaO + CO₂
   b) C + O₂ → CO₂
   c) Fe₂O₃ + 3CO → 2Fe + 3CO₂
   d) 2H₂O₂ → 2H₂O + O₂
   Answer: a) CaCO₃ → CaO + CO₂
10. Which of the following is reduced in the reaction: 2MnO₂ + 16H⁺ + 5C₂O₄²⁻ → 2Mn²⁺ + 10CO₂ + 8H₂O?
    a) MnO₂
    b) H⁺
    c) C₂O₄²⁻
    d) CO₂
    Answer: a) MnO₂
11. Application in Daily Life
    Bleaching action of Cl₂ is due to:
    a) Oxidizing nature
    b) Reducing nature
    c) Hydrolysis
    d) Sublimation
    Answer: a) Oxidizing nature
12. Bleaching action of SO₂ is due to:
    a) Oxidizing nature
    b) Reducing nature
    c) Hydrolysis
    d) Condensation
    Answer: b) Reducing nature
13. Rusting of iron is an example of:
    a) Reduction only
    b) Oxidation only
    c) Electrochemical redox reaction
    d) Photochemical reaction
    Answer: c) Electrochemical redox reaction
14. Which of the following acts as both oxidizing and reducing agent?
    a) H₂O₂
    b) O₃
    c) SO₂
    d) All of these
    Answer: d) All of these
15. Which reaction shows auto-oxidation and auto-reduction?
    a) 2H₂O₂ → 2H₂O + O₂
    b) H₂ + Cl₂ → 2HCl
    c) NaOH + HCl → NaCl + H₂O
    d) CaCO₃ → CaO + CO₂
    Answer: a) 2H₂O₂ → 2H₂O + O₂
16. Extra Practice
    In Fe₂O₃ + 3CO → 2Fe + 3CO₂, the reducing agent is:
    a) Fe₂O₃
    b) Fe
    c) CO
    d) CO₂
    Answer: c) CO
17. In the same reaction, the oxidizing agent is:
    a) Fe₂O₃
    b) CO
    c) Fe
    d) O₂
    Answer: a) Fe₂O₃
18. In which medium is KMnO₄ a stronger oxidizing agent?
    a) Acidic
    b) Basic
    c) Neutral
    d) All
    Answer: a) Acidic
19. In acidic medium, Mn in KMnO₄ is reduced from +7 to:
    a) +4
    b) +6
    c) +2
    d) 0
    Answer: c) +2
20. In neutral medium, Mn in KMnO₄ is reduced from +7 to:
    a) +2
    b) +4
    c) +6
    d) 0
    Answer: b) +4