Question

What must happen to the aluminium ion to convert it back to aluminium metal? The formula is 3 Ag2S + 2 Al --> 6 Ag + Al2S3

Answer 1

The Aluminium ion is in the form Al³⁺ . It has gone from oxidation state 0 to +3 during the given reaction. It shows that it has gone under oxidation reaction.

To convert aluminium ion back to aluminium metal, it has to undergo reduction.

Reduction : Al³⁺ + 3e^- ------> Al

This can be done using Compact Aluminium Production process.It is the process to obtain aluminium metal from aluminium sulphide at an industrial scale. This is an electrolysis process in which following reaction takes place at cathode and anode.

Cathode : 2Al³⁺ + 6e^- -------> 2Al

Anode: 2AlS₃^3- --------> Al₂S₃ + 1.5S₂(g) + 6e^-

Overall : Al₂S₃ ---------> 2Al +1.5S₂(g)