Splitting water at home

[woelen]

At the cathode you get hydrogen and hydroxide.

 

2H2O + 2e ---> H2 + 2OH(-)

 

The 2e are supplied by the voltage source and the hydroxide ions OH(-) remain dissolved in the liquid.

 

With the Fe(2+) ions, formed at the anode, they react as follows:

 

Fe(2+) + 2OH(-) ----> Fe(OH)2

 

Fe(OH)2 is an off-white solid, which becomes green when even the slightest trace of Fe(OH)3 is contained in it. Lateron it becomes brown, due to aerial oxidation:

 

4Fe(OH)2 + O2 + 2H2O --> 4Fe(OH)3

 

The latter is brown/red.

 

The stuff you see at the surface most likely is due to very finely suspended iron hydroxide or other small particles, which remain floating in the water. Due to these particles, bubbles do not break apart at once when they reach the surface, but remain floating on the surface for a while.

[vrus]

That explains it. Thnx.

[rthmjohn]

So I'm under the assumption that when I boiled off the water in my sample of Fe2O3 containing lots of iron(III)chloride and hydroxide, my anhydrous rust still had the impurities in it?

[paullywaully]

Im just getting started into water electrolysis and was wondering if i could get any points in the right direction as far as supplies for anodes and cathodes as well any other helpfull suggestions ????ty

[rthmjohn]

All you really need are some nails, a dc converter (preferably a train set converter), some gator clips, and a beaker. An electrolyte such as sulfuric acid works great. If you can't get those, just use table salt (NaCl). Eventually these electrodes will corrode, so you might invest in some platinum coated wire (get it off ebay), which won't corrode at all. btw do you plan on collection the H2 and O2 gas?

[electrolyzer]

it is electrolysis of water

 

you`re just making it a more conductive' date=' thus "faster", sulphuric acid will work just as well too.[/quote']

 

Sodium Hydroxide really makes electrolysis of water faster. But can someone possibly explain what happens when NaOH is added? I mean, what happens to the ions and all the chemisty behind that.

 

----------------------------------*---------------------------------------

 

Now I have a problem which I think has nothing to do with the addition of NaOH. Strangely enough, I'm not obtaining the usual 1:2 ratio of oxygen and hydrogen, but rather 1:4 ratio approx. For every volume of oxygen produced, I'm obtaining 4 or 5 volumes of hydrogen. What am I doing wrong??

[paullywaully]

i m tryen to get a working system togeather to gather as much hydrogen from water and sunlight as i can initial ivestment of some capital is okay as long as the system is proven and reliable

[rthmjohn]

you should check out uniteduclear.com. they've got a solar powered electrolyzer that makes large amounts of H2 gas. The cost is quite high, mind you.

[calbiterol]

Instead of using solar cells perse, use parabolic reflectors to drive stirling cycle engines. It's much more efficient and cheaper by far.

[RVonse]

I hope this is not too off topic for the thread but was wondering if anyone knew how the commercial water splitters used by the professionals were made. I have heard they have a special membrane placed between the carbon electrodes which somehow passes ions but not hydrogen and oxygen gas molecules? Apparently thats how they can get pressurized hydrogen straight off of the conversion without using a compressor?

 

Does anyone happen to have information on this? Exactly what is the membrane made out of?

[calbiterol]

You could google it...

 

That's about all I can say though, because I am by no means familiar with commercial electolysis of water. I do know that they usually don't electrolysize.

[jrayj]

I heard somewhere it was made of asbestos.

[insane_alien]

its not made of asbestos. asbestos would be crap for it.

 

i'm thinking it is the same as the proton exchange membrane used in fuel cells. and they are basically like fuelcells, just run in reverse.

[jrayj]

About the detonating gas earlier in this post. I filled ip a liter bottle with it and rigged up a fuse system. It went off with a huge BOOM!! but left the bottle completly intact save the lid was blown off. It was just a cheap mountain dew bottle not a gatorade bottle. This makes me think that since it doesn't really realease any gas just water vapor it doesn't have that much power save the noise. Ohh well just wanted to get that out there. Oh and DON'T try this or you'll probably blow your hand or house up like JWalker!!!

[KtownChemist]

i read if you add water to an alloy of gallium and aluminum it produces aluminum oxide and hydrogen

[jdurg]

That is correct. The Ga dissolves the aluminum oxide coating that covers all exposed aluminum and allows bare Al to react with water. Al is pretty reactive, but any time we typically encounter it the metal is covered in a very thin layer of the oxide which binds strongly to it preventing further reaction.

[jrayj]

Yeah I have to do a research project on the Aluminum Gallium alloy for Colloquium (spell?).

[frosch45]

how much hydrogen leaks through the plastic bottle, anyway? I always thought it was a tricky little blighter to trap.

 

Its annoying, the molecules are so incredibly small. If you're trying to store it, you can forget about it

 

About a year ago, I tried to store some hydrogen in a water bottle. Sealed that up in a plastic ziploc bag. I opened it a month later (to see if it had escaped), and it was completely gone. The bag and water bottle were sagging, and even when I stuck a match in there, nothing happened.

 

And just plain plastic balloons do a pretty bad job as well. I tried to keep one of those over night, it was filled with hyrogen so it floated, but by morning it was on the ground

[jrayj]

It's easy to set off but you have to do it within 5-10 minutes of making it.