Question

Which of the following is not an application of electrolysis? Type in the appropriate number here. ___

1. Humphrey Davy's discovery of Sodium and Magnesium
2. Gold plating of golden temple in Tirupathi
3. Making primary batteries.
4. Manufacture of NaOH and KOH
5. Synthesis of pure copper from impure copper

Answer 1

Making primary batteries is not an application of electrolysis. Primary batteries are electrochemical cells and they exclusively involve only spontaneous cell reactions.
Electrolysis has wide applications in industries. Let us look at some of the important applications which are as follows:
(i) Production of hydrogen by electrolysis of water.
(ii) Manufacture of heavy water $D_{2}O$
(iii) The metals like Na, K, Mg, Al are obtained by electrolysis of fused electrolytes.
(iv) Non-metals like hydrogen, fluorine, chlorine are obtained by electrolysis.
(v) In this method pure metal is deposited at cathode from a solution containing the metal ions Ag, Cu etc
(vi) Compounds like NaOH, KOH, white lead, $KMn{O}_4$ etc are synthesised by electrolysis.
(vii) Electroplating: The process of coating an inferior metal with a superior metal by electrolysis is known as electroplating.