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

Jul 2, 2018

Hydrogen gas and chlorine gas

#### Explanation:

In electrolysis of $N a C l \left(a q\right)$, we have $N {a}^{+}$ and $C {l}^{-}$ aqueous ions, and also water molecules $\left({H}_{2} O\right)$. When a current passes through, the water molecules also split into ${H}^{+}$ ions and $O {H}^{-}$ 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:

$2 {H}^{+} + 2 {e}^{-} \to {H}_{2} \left(g\right) \uparrow$

At the anode, chlorine ions get oxidized to form chlorine gas opposed to hydroxide ions $\left(O {H}^{-}\right)$. That's because the concentration of chlorine ions is greater than the hydroxide ions, and the reduction of $C {l}^{-}$ ions is more practical.

The oxidation equation is then:

$2 C {l}^{-} - 2 {e}^{-} \to C {l}_{2} \left(g\right) \uparrow$

And then, $O {H}^{-}$ ions and $N {a}^{+}$ ions are therefore left in the solution. They combine to make sodium hydroxide $\left(N a O H\right)$. 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.