37 public questions tagged with this topic.
In S₈ + 8O₂ → 8SO₂, S (0) is oxidized to +4, and O (0) is reduced to -2.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Electrode Potential and Electrochemical Series and Galvanic Cells
Reduction involves electron gain. I (0 in I₂) becomes -1 in HI, gaining electrons.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Electrode Potential and Electrochemical Series and Galvanic Cells
Oxidation is loss of electrons. H₂ (0) becomes H+ (+1) in HCl, losing electrons.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Electrode Potential and Electrochemical Series and Galvanic Cells
S (0) becomes +6 in SO₃. Change = +6 - 0 = 6 electrons per S atom.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Electrode Potential and Electrochemical Series and Galvanic Cells
S (+2 avg. in S₂O₃²−) to +6 in SO₄²−: 4 S lose 4 × (6 - 2) = 16 electrons total. Per Na₂S₂O₃ = 16/2 = 8.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Electrode Potential and Electrochemical Series and Galvanic Cells
As (0 to +3 in As₂S₃): 2 As lose 6 electrons total. Per As = 6/2 = 3 electrons.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Classical and Electronic Concept of Redox and Oxidation Number
F (0 in 2F₂) to -1 in 4HF: 4 F atoms gain 4 electrons total. Per F₂ (2 F atoms) = 4/2 = 2 electrons.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Balancing Redox Reactions - Oxidation Number Method and Half Reaction
Cu (+2 to +1): 2 Cu atoms gain 2 electrons. I (-1 in 4KI) to 0 in I₂: 2 I atoms lose 2 electrons. Total = 2.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Balancing Redox Reactions - Oxidation Number Method and Half Reaction
In 4Fe + 3O₂ → 2Fe₂O₃, Fe (0 to +3) is oxidized, and O₂ (0 to -2) is reduced, making it a redox reaction.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Balancing Redox Reactions - Oxidation Number Method and Half Reaction
In Br₂ + H₂S → 2HBr + S, Br (0) is reduced to -1 in HBr.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Applications of Redox Reactions and Disproportionation
In FeCl₃ + 3NaOH → Fe(OH)3 + 3NaCl, no element changes oxidation state (Fe: +3, Na: +1, Cl: -1, O: -2, H: +1).
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Applications of Redox Reactions and Disproportionation
S (+4 in SO₂) to 0 in S: 1 S gains 4 electrons. 2 H₂S (S: -2 to 0): 2 S lose 4 electrons total. Per SO₂ = 4.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Applications of Redox Reactions and Disproportionation
