4.3.5 Representation of reactions at electrodes as half equations

• Oxidation occurs at the positive electrode (anode) during electrolysis.


  True
• Steps to balance a half equation

  1️⃣ Identify the oxidation or reduction reaction

  2️⃣ Determine the number of electrons transferred

  3️⃣ Balance the atoms involved

  4️⃣ Balance the charge by adding electrons

  5️⃣ Balance remaining atoms with H₂O or H⁺ ions
• Balancing half equations helps determine the overall balanced equation for electrolysis.


  True
• Where does oxidation occur in electrolysis?

  Positive electrode (anode)
• Half equations represent the reduction and oxidation reactions occurring at the positive (anode) and negative (cathode) electrodes during electrolysis
• The significance of half equations is that they help understand the overall reaction and products formed during electrolysis.
• Reduction in electrolysis occurs at the cathode, where electrons are gained.


  True
• Match the electrolyte with its anode and cathode reactions:

  Sodium Chloride (NaCl) ↔️ 2Na⁺ + 2e⁻ → 2Na

  Copper Sulfate (CuSO₄) ↔️ Cu²⁺ + 2e⁻ → Cu

  Water (H₂O) ↔️ 2H₂O + 2e⁻ → H₂ + 2OH⁻
• At the cathode, reduction occurs, where electrons are gained and the species is reduced.
• At the negative electrode (cathode), reduction occurs where electrons are gained
• When balancing half equations, determine the number of electrons transferred
• Match the electrolyte with its balanced half equations:

  Sodium Chloride (NaCl) ↔️ Oxidation: 2Cl⁻ → Cl₂ + 2e⁻ Reduction: 2Na⁺ + 2e⁻ → 2Na

  Copper Sulfate (CuSO₄) ↔️ Oxidation: 2H₂O → O₂ + 4H⁺ + 4e⁻ Reduction: Cu²⁺ + 2e⁻ → Cu

  Water (H₂O) ↔️ Oxidation: 2H₂O → O₂ + 4H⁺ + 4e⁻ Reduction: 2H₂O + 2e⁻ → H₂ + 2OH⁻
• Reduction in electrolysis involves the gain of electrons.


  True
• At the positive electrode (anode), oxidation occurs.


  True
• Match the electrode with its reaction:

  Positive (Anode) ↔️ Oxidation

  Negative (Cathode) ↔️ Reduction
• Steps for balancing half equations

  1️⃣ Identify the reaction: Oxidation or reduction

  2️⃣ Balance atoms: Start with the element being oxidized or reduced

  3️⃣ Balance charge: Add electrons to the appropriate side

  4️⃣ Balance oxygen: Add water molecules

  5️⃣ Balance hydrogen: Add hydrogen ions
• To ensure a half equation is balanced, check that the number of atoms and charges are equal on both sides.
• In the electrolysis of NaCl, the anode half equation is 2Cl⁻ → Cl₂ + 2e⁻.


  True
• What do half equations represent in electrolysis?

  Reduction and oxidation
• Why are half equations significant in electrolysis?

  Understanding overall reactions
• How is charge balanced in a half equation?

  By adding electrons
• Half equations help determine the overall balanced equation for the electrolysis
• At the negative electrode (cathode), electrons are gained during reduction.

  True
• In electrolysis, oxidation takes place at the anode, where electrons are lost and the species is oxidized.
• Balancing half equations helps predict the products formed in electrolysis.


  True
• Steps for combining balanced half equations

  1️⃣ Ensure electron transfer is equal

  2️⃣ Add the equations, canceling out electrons

  3️⃣ Check the overall balanced equation