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 cathode; attracts cations; reduction
carbon anode; attracts anions; oxidation
molten sodium chloride
porcelain crucible
pipeclay triangle
HEAT STRONGLY
tripod

4. 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
Na+(l) + e Na(l)
at the anode, Cl- ions give away electrons to become Cl2; Cl- ions are discharged
2Cl-(l) Cl2(g) + 2e-
overall reaction
2NaCl(l) Na(l) + Cl2(g)

5. electrolysis of molten compounds
electrolysis of molten sodium chloride
electrons flow from battery into cathode
electrons flow from anode into battery
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
Molten Electrolyte
Product at Cathode
Product at Anode
calcium chloride, CaCl2
calcium, Ca
chlorine, Cl2
sodium iodide, NaI
sodium, Na
iodine, I2
lead(II) oxide, PbO
lead, Pb
oxygen, O2