$(i)$ Explain the steps for extraction of copper from its sulphide ore. Write the balanced equations involved in the process.
$(ii)$ What is meant by refining of metals? Draw a diagram of electrolytic refining of copper and name the substances used as cathode, anode, and the electrolyte.

(N/A) $(i)$ Extraction of copper from its sulphide ore $(Cu_2S)$:
$(a)$ Roasting: The sulphide ore is heated in the presence of excess air to convert it into copper$(I)$ oxide.
$2Cu_2S(s) + 3O_2(g) \xrightarrow{\text{heat}} 2Cu_2O(s) + 2SO_2(g)$
$(b)$ Reduction: The copper$(I)$ oxide is then heated with more copper$(I)$ sulphide to obtain copper metal.
$2Cu_2O(s) + Cu_2S(s) \xrightarrow{\text{heat}} 6Cu(s) + SO_2(g)$
$(ii)$ Refining of metals: It is the process of removing impurities from the crude metal obtained after reduction to get pure metal.
Electrolytic refining of copper:
Anode: Impure copper block.
Cathode: Pure copper strip.
Electrolyte: Acidified copper sulphate solution $(CuSO_4 + H_2SO_4)$.