ELECTROLYSIS

ELECTROLYSIS

1. WHAT IS ELECTROLYSIS?

   • The decomposition of a compound using electricity.
     • Negative electrode-cathode
     • Positive electrode-anode
     • Compound must be molten not solid!

2. HOW DOES LEAD BROMIDE DECOMPOSE?

   • Lead Bromide - Lead + Bromine Gas
   • oppositely charged ions are attracted to oppisetly charged electrodes;
   • CATIONS ARE POSITIVE IONS (metal ions and hydrogen).
   • ANIONS ARE NEGATIVE IONS (non-metal ions).

3. SUMMARY

   • All ionic compounds when molten can be decomposed using electrolysis.
   • Cations travel to the cathode.
   • Anions travel to the anode
   • Non-metal always forms at the anode.
   • The metal and hydrogen always forms at the cathode.
   • The molten substance been electrolysed is called the electrolyte.
   • The electrodes do not involve themselves with the reaction because of the material.

4. THE ELECTROLYSIS OF SOLUTIONS

   • products from the salt solution will be different to the molten solution because there is water, which produces ions.
   • During electrolysis, these ions compete with the metal and non-metal ions
   • The more reactive a metal is the more it prefers being ions.
   • If a less reactive metal, such as copper or silver is present it would rather accept the electrons than H+.
     • Hence, the metal forms at the cathode

5. THE ELECTROLYSIS OF SALTY WATER

   • This industry has been based around the electrolysis of brine, salty water
   • Brine - Sodium Hydroxide + Chlorine + Hydrogen
     • At the Cathode-Hydrogen bubbles off
     • At the Anode- Chlorine bubbles off
     • Na+ and OH- ions are left behind, which means a solution of sodium hydroxide forms.
   • products from the electrolysis of brine
     • sodium hydroxide
       • soaps, detergents and paper
     • Chlorire
       • solvents, bleach, drugs, hydrochloric acid , paints and dyes
     • Hydrogen
       • fuel for rockets and nylon.

6. LEARN CAlCULATIONS