What is the electrolysis of sodium chloride?

Electrolysis of sodium chloride, also known as the chlor-alkali process, is a electro chemical reaction used to produce chlorine and sodium hydroxide (NaOH) by the electrolysis of aqueous sodium chloride (NaCl). The process involves the use of an electrolytic cell, consisting of two electrodes submerged in the saltwater solution.

 

The two electrodes used in the process are the anode and the cathode. Both the anode and cathode are made of titanium, which has the advantage of corrosion resistance.

 

At the anode, the chloride ions (Cl-) are oxidized to chlorine gas (Cl2), which is released into the air as a gas. The reaction at the anode is as follows:

 

Anode 2Cl- → Cl2 + 2e-

 

At the cathode, water (H2O) is reduced to hydrogen (H2) gas and hydroxide ions (OH-). The reaction at the cathode is as follows:

 

Cathode 2H+ + 2e- → H2

 

2H2O + 2e- → H2 + 2OH-

 

The sodium ions (Na+) present in the sodium chloride solution are not involved in the electrolysis process and remain in the solution as sodium ions.

 

Differences and reasons for electrolysis of sodium chloride and electrolysis of molten sodium chloride:

Electrolysis of molten sodium chloride can only produce sodium metal and chlorine gas because only sodium and chloride ions are present.

 

The product of electrolysis sodium chloride are hydrogen gas, chlorine gas and sodium hydroxide. When electrolyzing aqueous solutions of sodium chloride, because there are sodium ions, chloride ions, hydrogen ions and hydroxide ions in the solution, their ability to gain and lose electrons is different, H+ is easier to gain electrons than sodium ions, so hydrogen gas is generated at the cathode and chlorine gas is generated at the anode, and sodium hydroxide is generated in the solution, and the products are hydrogen gas, chlorine gas and sodium hydroxide.

Overall, the electrolysis of aqueous sodium involves the application of an electric current to a saltwater solution to produce chlorine gas and hydrogen gas at the anode and cathode, respectively. The process is key in the production of various chlorine-based products, as well as sodium hydroxide, which has a number of industrial applications.