Sciencemadness Discussion Board

Electrolysis Balanced Equation

ScienceHideout - 15-9-2012 at 13:08

Hey Everyone!

If there is one part of chemistry that I completely suck at, it is electrochemistry. Great at organics and inorganics, what I usually do in my lab, but I NEVER run electrolysis. Yeah, I got all the redox stuff down, and the eV, but you couldn't get much more about electrochem out of me.

But... my cousin has a question for me, and I told him I don't know how to answer it, but some kind person on sciencemadness will!

Trying to teach him how to calculate % yield from stoiciometry, and we need to know the reaction- the balanced equation- for the electrolysis of KCl into KClO3.

Typed in "Chlorate electrolysis" on search engine, and nothing like this came up under topics...

Thanks in Advance!

weiming1998 - 17-9-2012 at 00:57

Quote: Originally posted by ScienceHideout  
Hey Everyone!

If there is one part of chemistry that I completely suck at, it is electrochemistry. Great at organics and inorganics, what I usually do in my lab, but I NEVER run electrolysis. Yeah, I got all the redox stuff down, and the eV, but you couldn't get much more about electrochem out of me.

But... my cousin has a question for me, and I told him I don't know how to answer it, but some kind person on sciencemadness will!

Trying to teach him how to calculate % yield from stoiciometry, and we need to know the reaction- the balanced equation- for the electrolysis of KCl into KClO3.

Typed in "Chlorate electrolysis" on search engine, and nothing like this came up under topics...

Thanks in Advance!


Electrolysis of KCl to form KClO3 is actually a multi-stepped reaction. Nevertheless, I'll write the equations down.

At the cathode: 2H2O+2e- ---->2H2+OH-
Anode: 2Cl- ---->Cl2+2e-.

So now a mix of Cl2, H2, and KOH is produced. Now the KOH reacts with the Cl2 coming off at the anode to form KClO as:
2KOH+Cl2---->KCl+KClO+H2O. The resulting KCl returns to the cycle to be electrolysed, while the KClO disproportionates to form KClO3 and KCl as: 3KClO---->KClO3+2KCl. All this KCl produced as a by-product goes through this cycle again.