Question

During the extraction of metals, electrolytic refining is used to obtain pure metals.

(a) Which material will be used as anode and cathode for refining silver metal in this process?

(b) Suggest a suitable electrolyte also.

(c) In this electrolytic cell, where do we get pure silver after passing an electric current?

Answer 1

Explanation

Electrolytic refining is the method of using electricity to refine impure metals.

• In this process, the anode is made of impure metal, and the cathode is made of a strip of pure metal.
• A solution is made with a soluble salt of the same substance as the electrolyte. i.e., silver nitrate $\left({\mathrm{AgNO}}_3\right)$ is used as the electrolyte.
• When an electric current is transmitted, metal ions from the electrolyte are deposited as a pure metal in the cathode (refined silver), and the impure metal from the anode which is the crude silver dissolves in the form of ions into the electrolyte.
• Below the anode, the impurities metals are collected. It is called mud anode.
• The resulting silver will be $99.9\%$pure.

a) During extraction of metals, impure metal will be used as an anode, and pure metal is used as a cathode for refining silver metal by this electrolytic refining.

b) Silver Sulphate or Silver Nitrate is a suitable electrolyte for electrolytic refining.

c) Pure silver is obtained on the cathode.