Th e diagram shows the electrolysis of alumina (aluminium oxide) purifi ed from bauxite.
1 a What is the formula for aluminium oxide?
b What ions are present in aluminium oxide?
c What is the purpose of the cryolite in the process?
2 Write down half-equations for the processes occurring during electrolysis at:
a the anode:
b the cathode:
3 Complete the two statements.
a Oxidation ( of electrons) occurs at the .
b Reduction ( of electrons) occurs at the .
4 Th e graphite anodes have to be replaced regularly. Why is this?
5 Why is it so much more cost-eff ective to recycle aluminium than to extract new aluminium?
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