Electrolysis Overview

Definition and Purpose

• Electrolysis: A process that means "splitting up with electricity."
• Used to separate elements in ionic compounds using electrical current.

Key Concepts

• Electrolyte: A liquid or solution containing free-moving ions. Can be:
  • Soluble ionic compounds (e.g., Copper sulfate dissolved in water).
  • Insoluble ionic compounds (e.g., Lead bromide, which must be melted).

Equipment Needed

• Beaker: Holds the electrolyte.
• Electrodes:
  • Anode: Positive electrode.
  • Cathode: Negative electrode.
  • Made of metal or carbon.
• Wire: Connects electrodes, allowing electron flow.
• Power Supply: Drives electron flow from a battery.

Process of Electrolysis

• Electrolysis of Lead Bromide:
  • Molten Lead Bromide contains:
    • Positive Lead ions.
    • Negative Bromide ions.
  • Ionic Movement:
    • Bromide ions move to the anode.
    • Lead ions move to the cathode.
  • Discharge of Ions:
    • Bromide ions lose electrons (oxidation) and form bromine gas.
    • Lead ions gain electrons (reduction) and form molten lead.

Chemical Reactions

• Anode Reaction:
  • Bromide ions oxidized to bromine, releasing one electron each.
• Cathode Reaction:
  • Lead ions reduced by gaining two electrons to form pure lead.

Overall Electron Transfer

• Electrons from bromide ions travel to the anode, through the wire, to the cathode.
• This electron transfer process allows conversion of ions back to neutral elemental forms.

Future Topics

• Electrolysis of metal oxides.
• Electrolysis of aqueous solutions.

Further Learning

• Videos and resources are available at Cognito's website for deeper learning and tracking progress.