Question

With the help of labelled diagram explain how copper metal is purified after extraction.

Answer 1

Electrolytic Refining means refining by electrolysis.
Many metals like copper, zinc, tin lead are refined by this method.

Process Of electrolytic Refining :

--> The apparatus consist of Electrolytic tank containing acidified copper sulphate solution as electrolyte.

--> A thick block of impure copper metal is made anode .

---> A thin strip of pure copper metal is made as cathode.

On passing electricity, Impure copper from the anode dissolves and goes into CUSO4 solution and pure copper from the copper sulphate solution deposits on the cathode .

Thus pure copper metal is produced at cathode . The soluble impurities goes into the solution whereas insoluble impurities settles down at anode as anode mud.

Chemical reaction :
 At cathode : Cu²⁺ + 2e  ---->Cu

At anode : Cu - 2e---->Cu²⁺

Answer 2

In the purification of copper by electrolytic refining, the strip of impure copper metal is made the anode and a strip of pure copper metal is the cathode. A solution of copper sulphate is used as the electrolyte. When current is passed through the electrolyte, pure copper from the anode dissolves in the electrolyte. An equivalent amount of pure copper from the electrolyte is deposited on the cathode. The soluble impurities go into the solution, where as the insoluble impurities remain in the solution and are deposited at the bottom of anode as anode mud.

Following reactions take place at anode and cathode

Anode : Cu ---------> Cu+2 + 2e-

cathode : Cu+2 + 2e- --------> Cu