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Author: Subject: Potassium Chloride electrolysis
Manifest
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[*] posted on 11-7-2013 at 13:39
Potassium Chloride electrolysis


I have run the electrolysis for over 2 hours now, at 2.5 amps.

I used a carbon anode and a brass nail cathode.

When I took it off the electrolysis and filtered the carbon particles out I was left with a brownish solution.

I put this in an ice bath for about an hour to precipitate out the Potassium Chlorate but got nothing.

Does anyone know what I did wrong?
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Manifest
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[*] posted on 11-7-2013 at 14:24


I am going to run the same electrolysis with a more concentrated solution with 5 amps overnight.

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[*] posted on 11-7-2013 at 14:37


You put 5 Ah into the cell. This is equivalent to 0.187 mol of electrons. It takes 6 mol of electrons (under ideal conditions) to make one mole of chlorate. Therefore, you made AT MOST 31 mmol of chlorate. With your electrode choice, and assumed lack of pH control, I'd estimate your efficiency to be no more than 50%.

The answer to you question is that you didn't make enough chlorate for it to form a precipitate.




As below, so above.
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watson.fawkes
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[*] posted on 11-7-2013 at 14:48


Quote: Originally posted by Manifest  
Does anyone know what I did wrong?
Does anybody know what you did?

It's not like you stated a number of important things, such as concentration, total volume, current density, etc.
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[*] posted on 11-7-2013 at 15:36


you mention current, but we should also examine current density. at different current densities and temperatures, instead of making chlorate you could make chlorite.

1. what is the surface area of the anode in contact with the solution?

2. what is the temperature of the solution during electrolysis?
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Manifest
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[*] posted on 12-7-2013 at 06:41


The electrolysis for 12 hours worked :P

I got a load of chlorate at the bottom, it had lots of carbon powder in it(expected)
So, I decided to dissolve the chlorate in a load of boiling water then filter this solution with the carbon bits in it and then the chlorate would crystalise out once I put it in an ice bath.

Well... It's been in the ice bath for about an hour and no crystals have formed. Does anyone know why?
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hyfalcon
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[*] posted on 12-7-2013 at 07:06


Reduce your volume by half, boiling till you see little crystals forming on the surface(saturated), cool to near freezing. As the temp approaches freezing your chlorate should fall out.

[Edited on 12-7-2013 by hyfalcon]
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[*] posted on 12-7-2013 at 08:33


I thought chlorate was really insoluble in water so when you freeze it it just drops out

<!-- bfesser_edit_tag -->[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: removed unnecessary quote(s)]

[Edited on 7/12/13 by bfesser]
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[*] posted on 12-7-2013 at 08:37


A given quantity of a low solubility compound will remain in solution if there is too much solvent. If you don't understand this fundamental concept, then you shouldn't even have potassium chlorate! Besides, I would say that it's moderately soluble in water. Learn to read and do a little of your own research before posting more of this nonsense.
<a href="http://en.wikipedia.org/wiki/Potassium_chlorate" target="_blank">
Quote:
Solubility in water:
7.19 g/100 ml (20 °C)
8.61 g/100 m: (25 °C)
57 g/100 mL (100 °C) <img src="../scipics/_wiki.png" />
</a>

[Edited on 7/12/13 by bfesser]




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[*] posted on 12-7-2013 at 09:49


Too bad, i'm keeping it! I do understand that, maybe i'm making myself out to be an idiot..

Can you tell me how that quote was unnecessary? I was replying to that guy

<!-- bfesser_edit_tag -->[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: removed unnecessary quote(s)]

[Edited on 7/12/13 by bfesser]
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[*] posted on 12-7-2013 at 09:52


There's no point in quoting the entire post immediately preceding yours, as it's obvious who you are replying to. We can all scroll and read. It's disruptive to the flow of the thread, and is unnecessary with this forum software. Thanks for asking, though.

[Edited on 7/12/13 by bfesser]




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watson.fawkes
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[*] posted on 12-7-2013 at 10:40


Quote: Originally posted by bfesser  
it's obvious who you are replying to.
No, it's not always obvious. Deducible, yes. Quickly deducible --> obvious, no.

Quoting an entire preceding post is usually pointless, but cutting down the quotation is perfectly fine, since it draw attention to a particular point, rather than a post as a whole. It's what I've done with this post.

I've also saved this message in a separate text file, in anticipation I'll need to repost it after vandalism to the above quotation.
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[*] posted on 12-7-2013 at 12:18


Okay, noted.

I am boiling the solution down now, should I add a little bit of water once crystals form?
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[*] posted on 12-7-2013 at 12:49


Now why would I do a thing like that, <strong>watson.fawkes</strong>? You're setting a perfect example of how quotes can be used effectively! :D
Wherever possible, I like to address members by name rather than use quotes. [example]




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[*] posted on 12-7-2013 at 13:06


Quote: Originally posted by bfesser  
Now why would I do a thing like that, <strong>watson.fawkes</strong>?
Because you've done it before, to this post of mine, which I had to restore.
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[*] posted on 12-7-2013 at 13:08


You missed the sarcasm.
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[*] posted on 12-7-2013 at 13:15


Back on topic:

<strong>Manifest</strong>, look up a solubility vs. temperature curve for potassium chlorate in water, and base your crystallization off that and your expected yield. I could easily find this for you, but it will be good practice for you to learn to do this on your own.




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[*] posted on 13-7-2013 at 03:14


After I got my crude 'chlorate' sludge after electrolysis:

I:

1.Added boiling water
2.Filtered
3.Went outside and boiled this down until crystals formed, then added a little water
4.When this cooled down slightly I put this in an ice bath.
5.Crystals formed

I let these crystals dry and I tested with a little sugar and an excess of chlorate and vice versa.

I lit it, nothing happened, the sugar just browned.

I tried burning my chlorate in a flame and of course I got that yellow sodium contamination.

I'm pissed, I spent some time doing this I was sure it would work.
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[*] posted on 13-7-2013 at 13:41


Could I recrystalise this once again to fix it?
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