contents

1. contents • Electrolysis of molten compounds • Electrolysis of solutions • Electroplating • Extraction of metals • Electric cells

2. electrolysis of molten compounds • an electrolyte is an ionic compound that conducts electricity; molten state or solution in water • molten ionic compounds and solutions of ionic compounds can conduct electricity due to presence of mobile ions that can carry current • electrolysis is the conduction of electricity by an electrolyte, leading to its decomposition • example: electrolysis of molten sodium chloride • inert electrodes (e.g. carbon electrodes) do not react in electrolysis

3. electrolysis of molten compounds electrolysis of molten sodium chloride ammeter to show current flowing battery + - carbon anode; attracts anions; oxidation carbon cathode; attracts cations; reduction molten sodium chloride porcelain crucible pipeclay triangle HEAT STRONGLY tripod

4. Na+(l) + e Na(l) electrolysis of molten compounds electrolysis of molten sodium chloride • molten sodium chloride contains Na+ and Cl- ions • at the cathode, Na+ ions take in electrons to become Na atoms; Na+ ions are discharged • at the anode, Cl- ions give away electrons to become Cl2; Cl- ions are discharged 2Cl-(l) Cl2(g) + 2e- • overall reaction 2NaCl(l) 2Na(l) + Cl2(g)

5. electrolysis of molten compounds electrolysis of molten sodium chloride electrons flow from anode into battery electrons flow from battery into cathode sodium metal produced molecules of chlorine gas produced sodium atom sodium ion attracted to cathode chlorine atom sodium ion takes electron from cathode chloride ion gives electron to anode chloride ion attracted to anode cathode anode

6. electrolysis of molten compounds electrolysis of other molten compounds • when a molten ionic compound is electrolysed, metal is produced at the cathode; non-metal is produced at the anode