Question

A piece of impure copper metal is given to you. Describe briefly how will
you purify it by using the chemical effect of current.
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Answer 1

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⟶cu²+2e–

Cathode:-( cu²^+) +2e– ⟶ CU