electrolysis

• passing an electric current through ionic substances that are molten eg. lead bromide, or in solution breaks them down into elements. (electrolysis) and the substance broken down is called the electrolyte
• during electrolysis positively charged ions move to the negative electrode (cathode) and negatively charged ions move to the positive electrode (anode)
• oxidation - loss of electrons
• reduction - gain of electrons
• 2Cl- --> Cl2 + 2e-
• if there is a mixture of ions:

  • at the cathode, the products formed depend on the reactivity of the elements involved
  • at the anode, the products formed also depend on the relative concentration of the ions present
• electrolysis is used to electroplate objects. this may be for reasons such as appearance, durability and prevention of corrosion. includes copper plating and silver plating
• aluminium forms at negative electrode (cathode), oxygen forms at positive electrode (anode). positive electrode made of carbon which reacts with the oxygen to produce carbon dioxide
• electrolysis of sodium chloride solution produces hydrogen and chlorine and sodium hydroxide.

  sodium hydroxide - soaps

  chlorine- bleach and plastics