Chemical Effects of Electric Current

• Conduction of Electricity

  • Good Conductors
    • Metals (e.g., Copper, Iron)
    • Allow electric current to pass easily
  • Poor Conductors (Insulators)
    • Materials like Rubber, Plastic, Wood
    • Do not allow electric current to pass easily
  • Liquids and Electricity
    • Distilled water (Poor conductor / Insulator)
    • Tap water / Saltwater (Good conductor due to dissolved salts and minerals)

• Chemical Effects of Electric Current

  • Definition: Passage of electric current through a conducting liquid causes chemical reactions
  • Common Effects
    • Formation of gas bubbles at electrodes
    • Deposits of metal on electrodes
    • Change in color of solutions

• Electroplating

  • Definition: Process of depositing a layer of any desired metal on another material using electricity
  • Purpose
    • Appearance (shiny finish)
    • Prevention of corrosion / rusting
    • Scratch resistance
  • Common Examples
    • Chromium plating on car parts and bath taps
    • Gold/Silver plating on cheap ornaments
    • Tin plating on food cans (prevents food from touching iron)

• Testing Conductivity of Liquids

  • Using a Tester
    • Battery source
    • Connecting wires
    • Bulb or LED (glows even with a weak current)
  • Alternative Magnetic Tester
    • Uses a magnetic compass placed near a wire
    • Deflection of the compass needle indicates electric current flowing through the liquid