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electrolysis of sodium chloride


chemist1138

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hey all, this is my first post on SFN

 

I've got a question about the electrolysis of sodium chloride to form sodium chlorate...from what I understand this topic comes up quite a bit. I'm not really interested about how to do it, just how it happens within the cell. Here is an explination according to this webpage here:

 

Theory

Mechanism of chlorate formation

The reactions taking place in chlorate cells are not fully understood even today. The theory of Foerster and Mueller regarding the reactions in chlorate cells, developed about 80 years ago, is the most accepted. The following reactions are said to take place at the electrodes:

 

At the anode:

 

2Cl- ---> Cl2(aq) + 2 electrons

At the cathode:

 

2H2O + 2 electrons ---> H2 + 2OH-

 

The dissolved chlorine gas can then react with water to give hypochlorous acid:

 

Cl2(aq) + H2O ---> HClO + H+ + Cl-

From this reaction it can be seen that if the chlorine does not dissolve but escapes to the atmosphere, no H+ will be generated to neutralise the OH- formed at the cathode and the pH of the electrolyte will increase.

 

The hypochlorous acid thus formed will react in acid-base equilibrium reactions with water to give hypochlorite ions and chlorine gas (dissolved). The exact concentrations of dissolved Cl2, ClO- and HClO depend on the pH, temperature and pressure among other things. In the solution, chlorate will be formed (mainly) by the following reactions:

 

2HClO + ClO- ---> ClO3- + H+ + 2Cl-

and

2HClO + ClO- +2OH- ---> ClO3- + 2Cl- + H2O

 

the bolded part is what I'm confused about...is this the equation that the bolded part is referring too?

 

HClO + H2O <---> H+ + ClO- + Cl2 (aq)

 

^^ I know that's not balanced...and for the life of me I can figure out how

 

Is that equation, and if so how do you balance it?

 

Thanks,

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