Answer 1

(a) at cathode
In electrolytic refining, pure metal is always deposited at the cathode. The impure metal is made anode (positive terminal) and a thin rod of pure metal is made cathode (negative terminal). The salt of the metal  is made electrolyte in the cell. When electricity passed through the cell, the impure metal dissolves in the electrolytic solution. The pure metal from the electrolytic solutions moves and gets deposited at the cathode.