Electrolysis

Electrolysis

Introduction

Before we go into the details of the application of electrolysis, we must first understand very clearly the process of electrolysis and how it works.

The word electrolysis has been derived from the two words “Electro” meaning electricity and “lysis” meaning analysis which means separation. So just be finding the root of the word, we can understand what it means. Electrolysis means the splitting of compounds using electricity.

Electrolysis In Molten State

When a salt in is an aqueous or molten state, then it breaks up into its ions. For exampleNaCl (s) Na+ (l) + Cl- (l)These ions formed have either a negative or positive charge. Since unlike charges attract each other, the positive ions move toward the cathode (negative electrode) and are called cations and the negative ions move towards the anode (positive electrode) and are called anions.

At the Anode, the anode is the positive electrode and so negatively charged ions called anions are attracted towards it. The anions are negatively charged which means that they have an excess of electrons. These electrons are taken by the anode and so the ion is neutralized and it becomes a molecule. Thus continuing with the same example of molten Sodium Chloride, this is the reaction at the anode.

2Cl- (l) - 2e- Cl2 (g)As you can see from the reaction, when the chloride ion touches the anode, it gets discharged and is released as chlorine gas.

At the CathodeThe cathode is the negative electrode and so positively charged ions called cations are attracted to it. The cations are positively charged which means that they have a shortage of electrons. The cation takes electrons from the cathode. Then the cation is neutralized and it too becomes a molecule.

Na+ (l) + e- Na (s)Again you can see from the reaction, when the sodium ion touches the cathode; it gets ...