1. Oxidation at the Anode: The anode is where oxidation occurs. This means electrons are lost from the species present at the electrode.
2. Chloride Ions' Tendency to Lose Electrons: Chloride ions (Cl-) have a strong tendency to lose electrons and become chlorine atoms. This is because chlorine is a highly electronegative element, meaning it has a strong attraction for electrons.
3. Formation of Chlorine Gas: When chloride ions lose electrons at the anode, they become chlorine atoms. These chlorine atoms then combine with each other to form chlorine gas (Cl2):
2Cl- → Cl2 + 2e-
Overall Process:
During the electrolysis of a solution containing chloride ions, the following process takes place at the anode:
* Chloride ions (Cl-) migrate towards the positive anode.
* Chloride ions lose electrons (oxidation) and become chlorine atoms.
* Chlorine atoms combine to form chlorine gas (Cl2), which is then released from the solution.
In summary: Chlorine gas forms at the positive electrode because chloride ions are oxidized at the anode, losing electrons and forming chlorine atoms that combine to form chlorine gas.
