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.

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