Electrolysis of Molten Ionic Compound
Example – Electrolysis of MOLTEN Lead (II) Bromide
Figure above shows the apparatus set up for electrolysis of molten lead (II) bromide.
The electrolysis process start when lean (II) bromide start melting.
|At the Cathode||At the Anode|
When electricity is flowing, a silvery deposit of lead metal forms on the cathode. In fact, as it is molten, it is more likely to drip off in a molten blob.
When electricity is flowing, brown fumes of bromine gas are seen at the anode.
Pb2+ + 2e —> Pb
2Br– —> Br2 + e
PbBr2 —> Pb + Br2
At the Anode
- The negatively charged bromide ions move to the positive anode
- each bromine ion loses an electron to form a bromine atom.
- two of these newly formed atoms combine to form a bromine molecule (bromine gas).
At the Cathode
- The positively charged lead(II) ions, move to the negative cathode,
- each ion gains two electrons to form a lead atom.