Question

How will u separate gold from a mixture of gold and copper fillings.

Answer 1

It can be separated by electro-refining process. As per electrochemical series, Cu is strong reducing agent as compared to gold therefore when the mixture of Cu and Au are used as anode in electrolytic cell, the flow of gold takes place to cathode and reduced earlier as compared to copper due to less reduction potential. In this way at cathode end, gold is separated first.