In a fuel cell, what is the cathode reaction?
Cathode: O₂ + 4H⁺ + 4e⁻ → 2H₂O .
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Variation of Conductivity with Concentration and Measurement
#cathode
12 public questions tagged with this topic.
Filter questions
During electrolysis of aqueous Na₂SO₄ with inert electrodes, 0.224 L of gas (STP) is collected at the cathode. How many
Cathode: 2H₂O + 2e⁻ → H₂ + 2OH⁻ . 1 mol H₂ (22.4 L) requires 2F. Moles = (0.224/22.4) = 0.01 mol , Charge = 0.01 × 2 × 96500 = 1930 C .
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Electrolytic Cells and Electrolysis and Faraday's Laws
In the electrolysis of aqueous CuCl₂ with inert electrodes, what is the product at the cathode?
Cathode: Cu²⁺ + 2e⁻ → Cu . Copper metal is deposited.
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Electrolytic Cells and Electrolysis and Faraday's Laws
A dry cell delivers 0.1 A for 19300 s. What mass of MnO₂ (molar mass 87 g/mol) is reduced at the cathode? (F = 96500 C/m
Charge = 0.1 × 19300 = 1930 C . Cathode: MnO₂ + H⁺ + e⁻ → MnO(OH) , 1 mol MnO₂ requires 1F. Faradays = (1930/96500) = 0.02 F , Moles = 0.02 mol , Mass = 0.02 × 87 = 1.74 g .
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Electrolytic Cells and Electrolysis and Faraday's Laws
In a mercury cell, what acts as the cathode during discharge?
Cathode: HgO + H₂O + 2e⁻ → Hg + 2OH⁻ . HgO is the cathode material.
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Electrolytic Cells and Electrolysis and Faraday's Laws
In a dry cell, what is the oxidation state of manganese in the cathode product MnO(OH)?
Cathode: MnO₂ + NH₄⁺ + e⁻ → MnO(OH) + NH₃ . In MnO₂ , Mn = +4; in MnO(OH) , Mn + 2(-2) + 1 = 0, Mn = +3.
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Corrosion and Applications of Electrochemistry
In a dry cell, what is the oxidation state of manganese in the cathode product MnO(OH)?
Cathode: MnO₂ + NH₄⁺ + e⁻ → MnO(OH) + NH₃ . In MnO₂ , Mn = +4; in MnO(OH) , Mn + 2(-2) + 1 = 0, Mn = +3.
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Corrosion and Applications of Electrochemistry
In a mercury cell, what is the reducing agent?
Reaction: Zn(Hg) + HgO(s) → ZnO(s) + Hg(l) . Zn is oxidized, so it’s the reducing agent.
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Corrosion and Applications of Electrochemistry
A mercury cell produces 0.5 g of Hg (atomic mass 200 g/mol) at the cathode. What mass of Zn (atomic mass 68 g/mol) is ox
Cathode: HgO + H₂O + 2e⁻ → Hg + 2OH⁻ , Moles = (0.5/200) = 0.0025 mol , Charge = 0.0025 × 2 × 96500 = 482.5 C . Anode: Zn → Zn²⁺ + 2e⁻ , Moles Zn = 0.0025 mol , Mass = 0.0025 × 68 = 0.17 g .
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Corrosion and Applications of Electrochemistry
In a lead storage battery during discharge, what is the oxidation state of lead in the cathode product?
Cathode: PbO₂ + SO₄²⁻ + 4H⁺ + 2e⁻ → PbSO₄ + 2H₂O . In PbSO₄, Pb = +2.
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Batteries - Primary Secondary and Fuel Cells
A fuel cell produces 0.448 L of H₂O vapor (STP) at the cathode from O₂. How many coulombs are involved? (F = 96500 C/mol
Cathode: O₂ + 4H⁺ + 4e⁻ → 2H₂O . 2 mol H₂O (44.8 L) requires 4F. Moles = (0.448/22.4) = 0.02 mol , Charge = (0.02/2) × 4 × 96500 = 0.04 × 96500 = 3860 C .
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Batteries - Primary Secondary and Fuel Cells
In a dry cell, what acts as the cathode?
In a dry cell, the cathode is a graphite rod surrounded by MnO₂.
Ref: NCERT Class 12 Chemistry > Chapter 2: Electrochemistry > Topic: Batteries - Primary Secondary and Fuel Cells