sodium is manufactured commercially by electrolysis of molten sodium chloride. explain why it is not possible to use sodium chloride solution for this.

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To understand why sodium chloride solution is not suitable for the commercial production of sodium by electrolysis, let's delve into the principles of electrolysis.

Electrolysis is a process that involves passing an electric current through an electrolyte, which is typically a molten compound or an aqueous solution. The electrolyte contains ions that are free to move, allowing the electric current to flow.

In the case of sodium chloride (NaCl) solution, it consists of water and dissolved sodium chloride. When an electric current is passed through the solution, the positive ions (cations) move towards the negative electrode (cathode), and the negative ions (anions) move towards the positive electrode (anode).

However, sodium ions (Na+) and chloride ions (Cl-) are not the only ions present in the solution. Water molecules (H2O) can also undergo electrolysis. At the cathode, water molecules can be reduced to form hydrogen gas (H2) and hydroxide ions (OH-), while at the anode, water molecules can be oxidized to produce oxygen gas (O2) and more hydroxide ions.

The reduction potential of water to form hydrogen gas (-2.3V) is more favorable than the reduction potential of sodium ions to form sodium metal (-2.71V). Consequently, at the cathode, water is preferentially reduced to hydrogen gas instead of sodium ions being reduced to sodium metal.

This selectivity issue prevents the direct electrochemical reduction of sodium ions in a sodium chloride solution, as the production of sodium metal is hindered by the competing reduction of water. Moreover, the presence of water also poses safety hazards due to its reaction with reactive metals like sodium.

To overcome these challenges, the commercial production of sodium primarily utilizes molten sodium chloride. By melting sodium chloride, the ions are freed from the solid lattice and can move freely. In this state, at high temperatures, only sodium ions are present for reduction at the cathode, ensuring the efficient production of sodium metal.

In summary, the use of sodium chloride solution for the electrolysis of sodium is ineffective due to the preferential reduction of water at the cathode. The utilization of molten sodium chloride allows for the exclusive reduction of sodium ions, ensuring that sodium metal can be produced commercially.