Oxidation and reduction in electrolysis - Higher

• What is the process of electrolysis used for?

  To break down electrolytes to form elements using electricity
• How can the products of electrolysis be predicted?

  By knowing the electrolyte used
• What is a half equation in electrolysis?

  • An equation involving ions and electrons
  • Describes the process happening at an electrode
• What is an electrode?

  A conductor used to establish electrical contact with a circuit
• What is the negative electrode called during electrolysis?

  Cathode
• What is the positive electrode called during electrolysis?

  Anode
• What happens to positively charged ions at the cathode during electrolysis?

  They gain electrons
• Write the half equation for sodium formation at the cathode.

  Na⁺ + e^- → Na
• Write the half equation for lead formation at the cathode.

  Pb²⁺ + 2e^- → Pb
• Write the half equation for hydrogen formation at the cathode.

  2H⁺ + 2e^- → H₂
• Balance the half equation for the formation of aluminium during electrolysis.

  Al³⁺ + 3e^- → Al
• What is the balanced half equation for the formation of calcium from a calcium ion?

  Ca²⁺ + 2e^- → Ca
• What happens to negatively charged ions at the anode during electrolysis?

  They lose electrons
• Write the half equation for chlorine formation at the anode.

  2Cl^- → Cl₂ + 2e^-
• Write the half equation for oxygen formation from oxide ions at the anode.

  2O^2- → O₂ + 4e^-
• Write the balanced half equation for the formation of oxygen from hydroxide ions.

  4OH^- → 2H₂O + O₂ + 4e^-
• Write the balanced half equation for the formation of bromine from bromide ions.

  2Br^- → Br₂ + 2e^-
• What is oxidation and reduction in terms of electrons?

  • Oxidation: Loss of electrons or gain of oxygen
  • Reduction: Gain of electrons or loss of oxygen
  • Reduction occurs at the cathode
  • Oxidation occurs at the anode
• What does OIL RIG stand for in electrolysis?

  Oxidation Is Loss, Reduction Is Gain