Question

The following is a sketch of an electrolytic cell used in the extraction of aluminium:

1. What is the substance of which the electrodes A and B are made? 

2. At which electrode (A or B) is the aluminium formed? 

3. What are the two aluminium compounds in the electrolyte C? 

4. Why is it necessary for electrode B to be continuously replaced?

Answer 1

1. Graphite or carbon 

2. At electrode A. 

3. Alumina (Aluminium oxide) and Cryolite (sodium aluminium fluoride). 

4. Because electrode B gets burnt away with oxygen produced.