Which process is used for the refining of silver?

In the extraction of nickel by the Mond process,the metal is obtained by:

In the electrolytic refining of metals,the electrolysis of an aqueous solution of its complex salt is performed using an impure metal as the anode and a strip of pure metal as the cathode. This method cannot be used for the refining of which of the following metals?

Aluminium is refined by

Cupellation method is used for the purification of which of the following metals?

Which of the following properties of pure metal makes it more useful than the corresponding alloy?