Sciencemadness Discussion Board

Electrolysis of Sodium chlorde with aluminum electrodes

shaheerniazi - 30-11-2013 at 04:00

I did an electrolysis of saltwith aluminum electrodes with a 9-volt battery and I got a white powdery substance on the negate electrode and at the bottom of the vessel in which I performed the electrolysis, is that aluminum hydroxide or aluminum oxide?

[Edited on 30-11-2013 by shaheerniazi]

bismuthate - 30-11-2013 at 05:04

Was it molten?

shaheerniazi - 30-11-2013 at 05:15

Oops Sorry! forgot to mention it was a solution.

bismuthate - 30-11-2013 at 05:32

It might be sodium aluminate formed by the reaction of (NaOH) with Al

[Edited on 30-11-2013 by bismuthate]

shaheerniazi - 30-11-2013 at 05:38

It has a grayish wight colour

shaheerniazi - 30-11-2013 at 05:40

Wikipedia says it is soluble in water and my powder is making a suspension in water.

homeIandsecurity - 30-11-2013 at 06:03



It is Aluminium Hydroxide, with Al metal impurities.

[Edited on 30-11-2013 by homeIandsecurity]

bismuthate - 30-11-2013 at 06:04

Ahh it's insoluble. I suspect impurities..
homeland security, wouldn't Al(OH)3 be attacked by the NaOH produced?

[Edited on 30-11-2013 by bismuthate]

homeIandsecurity - 30-11-2013 at 06:07

Quote: Originally posted by bismuthate  
Ahh it's insoluble. I suspect impurities..


It can't be aluminate...because it only occurs in basic solution...but Sodium Chloride in his case did not smell like Chlorine, meaning did not release any Chlorine.

Sodium Chloride isn't involved in any reaction there. Only water - Hydrogen hydroxide reacts with Al.
Only this:
H+ -> (H)
Al -> Al(3+)

[Edited on 30-11-2013 by homeIandsecurity]

shaheerniazi - 30-11-2013 at 06:37

Thanks guys! I am now labeling i with surety!

homeIandsecurity - 30-11-2013 at 06:42

Quote: Originally posted by shaheerniazi  
Thanks guys! I am now labeling i with surety!


Just filter that powder to separate all soluble chemicals and dry. Then, put it in HCl acid for test. If releases even one small bubble, you can be sure impurity is Al metal.

shaheerniazi - 30-11-2013 at 06:52

Yes! when I did the electrolysis small flakes of aluminium foil did some contamination of it.

homeIandsecurity - 30-11-2013 at 06:57

Have you noticed this...VERY INTERESTING!

Your foil will be transparent on some parts after electrolysis. I always thought, that is some thin plastic over it...like nylon...but guess what is it?

shaheerniazi - 30-11-2013 at 07:11

Hmm, You tell, I have no idea.

homeIandsecurity - 30-11-2013 at 07:20

TRANSPARENT OR INVISIBLE ALUMINIUM.

I am right now doing electrolysis and will post a new thread called TRANSPARENT/INVISIBLE ALUMINIUM with picture in beginnings!

shaheerniazi - 30-11-2013 at 07:27

Cool, but This never happened to my alluminum, will it work with water electrolysis with aluminum electrodes?

shaheerniazi - 30-11-2013 at 07:29

In the internet it says its aluminium oxynitride?

homeIandsecurity - 30-11-2013 at 08:11

Yes...it must be foil (even from chocolate is possible).

You must have sodium chloride...water alone doesn't work.

No, Al oxynitride is formed when burning aluminium in air.

shaheerniazi - 30-11-2013 at 08:17

When I burn it in air then it forms a white powder which is aluminium oxide, and I used the aluminium foil from the kitchen which is used for packing and when I did it then it formed a white crystaline powder on my foil, let me show you wait.

shaheerniazi - 30-11-2013 at 08:26


homeIandsecurity - 30-11-2013 at 08:55

Yes.
Al oxynitride is formed only when burning it in limited amount of air. Here is how to test: Just put it in water...if it smells like ammonia gas then you have some nitride also.

Did you burn it in stove or just with flame?

shaheerniazi - 30-11-2013 at 09:11

I used a stove.

bfesser - 30-11-2013 at 10:22

Quote: Originally posted by homeIandsecurity  
Yes...it must be foil (even from chocolate is possible).
It's plastic (or another non-metallic thin film coating on the foil)! <img src="http://clipartist.info/Art/April/facepalm_facepalm-999px.png" width="14" alt="facepalm" />

[Edited on 30.11.13 by bfesser]

woelen - 30-11-2013 at 12:32

@shaheerniazi: Do not reply to homeIandsecurity anymore. He is fooling you into all kind of stupid things and has fun of your confusion. He is a troll.

Zyklon-A - 30-11-2013 at 13:13

Quote: Originally posted by bismuthate  
Was it molten?

If NaCl was molten the aluminum would also melt.

Zyklon-A - 30-11-2013 at 13:18

Quote: Originally posted by bismuthate  
Was it molten?

If NaCl was molten the aluminum would also melt.

shaheerniazi - 30-11-2013 at 21:33

Yes Aluminium would melt at 660 celsius and salt melts at about 800 celsius, this would only work with inert electrodes like carbon or platinum. Though wont the sodium melt at these temperatures because its melting point is 97.72 celsius and boiling point is 880 celsius?

[Edited on 1-12-2013 by shaheerniazi]

elementcollector1 - 30-11-2013 at 21:50

Usually, yes, the sodium would boil off. This is why you use a eutectic of sodium chloride and calcium chloride, which if mixed in the right ratio lowers the boiling point to somewhere around 500-600 C.

shaheerniazi - 30-11-2013 at 22:04

I think ill make a separate thread discussing aboult molten salt electrolysis.:)

Zyklon-A - 10-12-2013 at 17:21

Quote: Originally posted by elementcollector1  
Usually, yes, the sodium would boil off. This is why you use a eutectic of sodium chloride and calcium chloride, which if mixed in the right ratio lowers the boiling point to somewhere around 500-600 C.

The Na should not boil unless the temp is above 882 C.
Also, I think you mean the melting point. ''which if mixed in the right ratio lowers the boiling point to somewhere around 500-600 C.''

Zyklon-A - 10-12-2013 at 17:23

Quote: Originally posted by shaheerniazi  
I think ill make a separate thread discussing aboult molten salt electrolysis.:)

There are already a few threads about that.;)

Zyklon-A - 10-12-2013 at 17:27

Quote: Originally posted by Zyklonb  
Quote: Originally posted by shaheerniazi  
I think ill make a separate thread discussing aboult molten salt electrolysis.:)

There are already a few threads about that.;)

But I guess it is easer to make a new thread than to revive an old one.;)