Electrolysis Flashcards
What is electrolysis?
Electrolysis means ‘splitting up with electricity’.
What is required for electrolysis to occur?
An electric current must be passed through an electrolyte.
What is an electrolyte?
A liquid or solution that can conduct electricity.
What happens to positive ions during electrolysis?
They move towards the cathode and gain electrons (they are reduced).
What happens to negative ions during electrolysis?
They move towards the anode and lose electrons (they are oxidised).
What is an electrode?
A solid that conducts electricity and is submerged in the electrolyte.
What occurs when ions gain or lose electrons during electrolysis?
They form the uncharged element and are discharged from the electrolyte.
Why can’t ionic solids be electrolysed?
The ions are in fixed positions and cannot move.
What can be electrolysed?
Molten ionic compounds, because the ions can move freely.
What is produced during the electrolysis of molten lead bromide at the cathode?
Lead (Pb).
What is produced during the electrolysis of molten lead bromide at the anode?
Bromine (Br2).
What is the purpose of using inert electrodes in electrolysis?
To prevent them from reacting with the electrolyte.
What is the half equation for the reduction of lead ions?
Pb2+ + 2e- → Pb.
What is the half equation for the oxidation of bromide ions?
2Br- → Br2 + 2e-.
What is the overall equation for the electrolysis of aluminium oxide?
2Al2O3 → 4Al + 3O2.
At the negative electrode during the electrolysis of aluminium oxide, what is produced?
Aluminium (Al).
At the positive electrode during the electrolysis of aluminium oxide, what is produced?
Oxygen (O2).
Fill in the blank: Electrolysis is used to extract __________ from their ores.
reactive metals.
True or False: Cryolite is used to lower the melting point of aluminium oxide.
True.
What is a consequence of using carbon electrodes in the electrolysis of aluminium oxide?
They need to be replaced regularly as they react with oxygen to produce carbon dioxide.
