What can we get from the electrolysis of NaCl in dissolved state?

1 Answer
Nam D.
Jul 2, 2018

Hydrogen gas and chlorine gas

Explanation:

In electrolysis of #NaCl(aq)#, we have #Na^+# and #Cl^-# aqueous ions, and also water molecules #(H_2O)#. When a current passes through, the water molecules also split into #H^+# ions and #OH^-# ions.

Since sodium is more reactive than hydrogen, it would have a higher tendency to stay as an ion, and so hydrogen will get reduced at the cathode, forming hydrogen gas.

The reduction equation for that is:

#2H^++2e^(-)->H_2(g)uarr#

At the anode, chlorine ions get oxidized to form chlorine gas opposed to hydroxide ions #(OH^-)#. That's because the concentration of chlorine ions is greater than the hydroxide ions, and the reduction of #Cl^-# ions is more practical.

The oxidation equation is then:

#2Cl^(-)-2e^(-)->Cl_2(g)uarr#

And then, #OH^-# ions and #Na^+# ions are therefore left in the solution. They combine to make sodium hydroxide #(NaOH)#. This is used to make bleach and many other products.

Together, this is one of the fundamental processes in the chlor-alkali industry, and this process can be called the electrolysis of brine.

Related questions
Impact of this question
1009 views around the world
You can reuse this answer
Creative Commons License