During the electrolysis of sodium chloride, chloride ions (Cl-) move to the positive electrode (anode) because of the principles of electrolysis and the movement of ions in an electric field.
In the electrolysis process, a direct electric current is passed through a solution (electrolyte) containing sodium chloride (NaCl) dissolved in water. The solution is typically referred to as brine.
At the anode (positive electrode), oxidation occurs. The anode attracts negatively charged ions or anions. In the case of sodium chloride, chloride ions (Cl-) are negatively charged and are attracted to the positively charged anode.
At the anode, chloride ions lose electrons and undergo oxidation, forming chlorine gas (Cl2). The half-reaction at the anode can be represented as follows:
2Cl- → Cl2 + 2e-
The released chlorine gas can then be collected as a product of the electrolysis process.
On the other hand, at the cathode (negative electrode), reduction occurs. In the case of sodium chloride electrolysis, water molecules (H2O) are reduced, forming hydrogen gas (H2) and hydroxide ions (OH-). The half-reaction at the cathode can be represented as follows:
2H2O + 2e- → H2 + 2OH-
To summarize, during the electrolysis of sodium chloride, chloride ions (Cl-) move to the positive electrode (anode) because they undergo oxidation and form chlorine gas as a product.