Question

Which one of the following is true in electrolytic refining?
A.Impure metal is made cathode.
B.Impure metal is made anode.
C.Impure metal is made of cathode and pure metal anode.
D.Both electrodes must be of pure metal.

Answer 1

Hint: Electrolytic refining is a process in which a particular metal is purified and, in this process, electrolysis is used in which oxidation and reduction process occurs. Generally, reduction takes place at cathode and oxidation at anode. So, the impure metal will become pure at one of the electrodes by gaining electrons and becoming neutral.

Complete step by step answer:
Electrolytic refining is the process of purifying a metal by using a process of electrolysis and in electrolysis current is passed in a solution to start a chemical reaction of oxidation and reduction and we have cathode and anode in the electrolysis process. Generally, reduction reaction takes place at cathode and oxidation reaction occurs at anode.
To purify the metal by electrolysis we take 2 strips of metal – 1 is of impure metal and 1 is of pure metal.
Let us take example of Copper purification by electrolytic refining
We took impure copper at anode and pure copper at cathode and dipped in \[CuS{O_4}\]solution.
So as the electricity is passed the reaction would occur as: -
Anode: - \[Cu \to {\text{ }}C{u^{2 + }}_{} + {\text{ }}2{e^ - }\](oxidation half reaction where copper starts losing electrons)
Cathode: - \[C{u^{2 + }}_{} + {\text{ }}2{e^ - } \to {\text{ }}Cu\](reduction half reaction)
Copper is depositing here (pure) coming from impure
Mud is impurity which gets settled down when reaction is taking place

So, the answer is option B i.e. impure metal is made at anode.

Note:
Electrolyte refining process is generally used for Copper, zinc and there are other methods as well to purify a metal in metallurgy and there are specific methods for specific metals like for iron, there is magnetic separation of pure iron from impure and many more.