Separate Hydrogen and Oxygen from Water Through Electrolysis

Electrolysis a method of separating elements by pushing an electric current through a compound. It is used in various industrial applications such as removing copper from its ore. It is also used to separate hydrogen and oxygen from water. Electrolysis isn't the most efficient way to obtain hydrogen, but it is one of the easiest and cheapest ways to "homebrew" hydrogen.

Hydrogen is the most abundant element in the universe. With the "green-energy" craze and talk of powering our future oil-free economy on hydrogen, it has gotten much attention in the last few years. Learning about this potential fuel of the future is important and interesting. Besides, hydrogen is a powerful fuel, and blowing stuff up in the name of science is fun .

Step 1: Electrolysis of Water - An Explanation

This section is an explanation of the electrolysis of water, feel free to skip it if you don't find it interesting.

2H2O(l) = 2H2(g) + O2(g)

As everyone knows a water molecule is formed by two elements: two positive Hydrogen ions and one negative Oxygen ion. The water molecule is held together by the electromagnetic attraction between these ions. When electricity is introduced to water through two electrodes, a cathode (negative) and an anode (positive), these ions are attracted to the opposite charged electrode. Therefore the positively charged hydrogen ions will collect on the cathode and the negatively charged oxygen will collect on the anode.

When these ions come into contact with their respective electrodes they either gain or lose electrons depending on there ionic charge. (In this case the hydrogen gains electrons and the oxygen loses them) In doing so these ions balance their charges, and become real, electrically balanced, bona fide atoms (or in the case of the hydrogen, a molecule).

The reason this system isn't very efficient is because some of the electrical energy is converted into heat during the process. There have been reports of 50%-70% efficiency, but I doubt that is possible in a home environment. Anyway, enough with the boring stuff, lets go make some gas!

Comments

[albapa]

This setup will produce chlorine on the anode which is a toxic and corrosive gas.

You should use sulphuric acid as this remains intact during the electrolysis. In addition, the electric conductivity is larger and hence the efficiency of your setup will be better.

[ecks51]

(removed by author or community request)

[triggernum5]

There is speculation that the paint used actually constituted thermite and was ignited.. Mythbusters actually surprised me by recreating that possibility..

[Snidely70448]

Thermite is a mixture of finely powdered aluminum and iron oxide (rust). Text book igniter is potassium perchlorate and sugar, or magnesium. The Arky uses it to destroy things in danger of capture by enemy forces, like machinery or documents in a safe. A thermite grenade will burn completely through a safe, engine block or gun(cannon) tube in a few seconds.

[El Mano]

What about thermite?

[lukeyj15]

GO MYTHBUSTERS!!!

[BlowgunSniper88]

Then what was burning so furiously? I heard they painted it with thermite, but the footage didn't look like a thermite reaction to me...

[geeklord]

Hey!, I got an idea! Lets paint a hydrogen (flammable) filled ballon with rocket fuel(highly flammable)!!!Somebody noticed this when they were making it right?

[Snidely70448]

Thrift shops (Goodwill, etc) often have power supplies from deceased electronic gadgets or a couple of bucks.

[SchneiderRL]

Well I glad You read your history. There nothing wrong with the process because it has been done before. For exsample Francois Isaac de Rivaz designed in 1807 the first hydrogen-fueled internal combustion engine.[32] Paul Dieges patented in 1970 a modification to internal combustion engines which allowed a gasoline-powered engine to run on hydrogen US 3844262. Now If people over a 100 yaers ago figure how to take a gas motor that ran on gas and make it run on hydrogen. You really believe with all the computer tec. that we have, we can't figure out how to hook them together to make it run really that sad. We have the knowlege but no one to put it together. What about superconducting metals or the fact that we can build fuel injecters for gas motors make the engine use less fuel. This are all Ideas that have never been really tested. It all about big oil stopping the little man from making something that could work better the the gas engine. There battaries that can run for years in other counties how hard could it be to put out more energy to the right set up to run it. Just a thought?

[Weregoat]

I have a question -

While this is a neat way to obtain hydrogen, what of the oxygen?
I guess without going too far in-depth, can we get breathable oxygen from water? Or is the Oxygen gas chemically different from the O2 we know and love (to breathe)?

I'm not very chemistry minded, and it's been years since I've even taken a course on science, but I'm wondering if it is possible to get breathable air from water.

[nox1468]

well, don't worry for not knowing. what you should know is that the oxygen molecules will collect near one lead of wire, the hydrogen will collect on the other. this is because water molecules are polarised, and one side is more positive than the other. this means that if you place a collector of some sort (like the test tube) on both leads, then one will fill with hydrogen, the other with oxygen. if you do this, be sure to not use something that reacts with oxygen as your electrolyte, or else the resulting gas could be toxic. but, as long as the electrolyte can't react with the oxygen, the atoms should conect into O2, or breathable oxygen.

[jitendrasahoo]

my name is jitendra sahoo my bike 149cc cbz bike start hydrogen start

[magesing]

Note: if you use NaCl (table salt) as your electrolyte, you will make more Cl2 (chlorine gas) then O2 (oxygen gas). If you are trying to make oxygen, this is not the correct choice of electrolyte. also node, you do NOT want to breath in chlorine gas.

[epicnoobpwn]

Can I use an engine's gas tank (lawnmower) as the hydrogen reservoir? How would I collect the hydrogen directly in the gas tank?

Can I hook up a motor to the driveshaft of an engine to generate the electricity instead of a battery?

Does hydrogen require oxygen to burn?

How many volts are required to create a decent amount of hydrogen? What contributes to how fast the electrolisys process is: volts, amps, or watts?

[x3n0c1dal]

Yes, you can, just fill it with salt water and place it in the container, like you would a test tube.

Anything that generates electricity can be used, really.

The chemical reaction known as combustion always requires oxygen.
2H₂ + O₂ → 2H₂O + heat

I am merely a high-schooler, but from what I know the watt is a unit of power. Also, the strength of the electricity is not relevant, as long it produces electricity.

[TwinMustang]

@ eXtremesomething This diagram is clearly drawn to indicate electron flow, with colours to indicate terminals. Red terminals are usually identified by the Plus sign (+) whereas electron flows from "Negative" to "Positive". Hope this helps.

[resistanceisfutileiflessthan1ohm]

hang on! hydrogen ions are positive H+ so surely they will collect over the negative electrode. avoid the salt as Cl gas will be produced, i don't think you need it as long as the water is not too pure.

[stevezettler]

This is a nice learning piece. However if you use salt as the electrolyte then you will get hydrogen and chlorine not oxygen. Try using washing soda or baking soda. For this experiment a teaspoon or less will do.
Cheers

[nkhan15]

A Pakistani engineer Make a water Kit & successfully Runs a suzuki car on water.

http://www.awaztoday.com/News-Talk-Shows/25740/Agha-Waqar-Ahmed-Proved-that-Water-can-be-used-instead-of-a-fuel-in-a-Car.aspx

[AgentPerry147]

Hello Guys Good eves!

Ammm! Is there a possibility that a car with its piston engines can be powered by only water (with of course the help of electrolysis) and totally replace the car's dependence from petroleum?

Well I have a hypothesis, the H2 and the O2 are both volatile materials and when mixed and crushed can power the pistons in a car engine.

Is this possible!

Any answer will be appreciated!

[oprator57]

My Dear
if u used H2 without O2 and mix it petroleum.

2Nd H2 peroduse equal to petroleum than its good for your car.

i m waiting your answer.


Asif ali
Pakistan.

[sjain24]

i was also thinking same as u were lol......
but there must be any prob otherwise it would be already invented

[RedAlert602]

Are you talking about liquid oxygen and hydrogen? Or the gases?

[earbreaker]

baking soda is safe? no side effect?

[eXtremeSomething]

Anode is positive , positive is a + symbol and is usually red, so there is something screwed up with that diagram.

[_Ry_]

I agree with extremesomething the diagram is wrong.

When salt(NaOH) is used as an electrolyte chlorine gas is present at the anode+. That is why it wont burn lol

Potassium hydroxide is a safe and inexpensive alternative if you want oxygen and hydrogen, 

Honestly Wikipedia explains it well.
http://en.wikipedia.org/wiki/Electrolysis_of_water

[_Ry_]

forgive me, salt(NaCL) 'Cl' being chlorine

here is a swf of the reaction with Potassium hydroxide(KOH)

[Timofte Andrei]

salt is NaCl! so in water that green-yellowish coloured thing is chlorine! DO NOT BREATH THAT GAS! MAKE'S YOUR LUNGS LIKE A WET SPONGE AND THAT MEANS A SLOW BUT PAINFULL DEATH!

[El Mano]

They're both ionic salts. NaCl produces Cl2, baking soda produces CO; what makes NaOH the salt of choice?

[squiggy2]

all three of those salts are equally effective - it's just that health risks must be considered.

Cl2 is highly toxic to the lungs - and has immediate consequences.

Prolonged exposure to CO causes CO poisoning, where CO bonds with your red blood cells, and the can no longer take in oxygen. This will go away after a while (weeks) if you don't get it so badly that you die. ie. better than CL2

NaOH is the safest because it produces no harmful byproducts.
However, if you are in a position where you can choose salts, go for a sulfate (as mentioned below) because it does not take part in any of the reactions, so you end up with just H2 and O2.
Sulfuric acid is a good one, and it can be found in off-the-shelf cleaning products (drain cleaner?)

[gauzz]

How about Bicarbonate or Sodium bicarbonate?

[squiggy2]

Sodium bicarbonate is the scientific name for baking soda. So see El Mano's reply. But in reference to that, @El Mano I've done some reading and to me it seems that bicarbonate is a fine electrolyte and does not react at all itself, unless it gets too hot, when it will decompose into CO2. What are your sources for saying it will electrolyse to CO?

[gauzz]

Yeah txh, I'm just looking something that won't injure me or kill me, somehing that will produce the purest hydrogen and oxigen as a result.

[squiggy2]

My personal favorite is sulfuric acid. You can buy it for ~$7/L at autobarn labeled as battery acid. It's a bit dangerous as it is in the bottle, but you can dilute it with 3 parts water, or keep it as is. As long as you don't spill it, it will produce pure hydrogen and oxygen, and never deplete. Once you've bought it, it's there forever. You can have it on your skin for a few minutes without bad things happening, after which you should wash your hands, but it does destroy clothes. Also make sure you use PVC or Perspex to contain it. Coke bottles will dissolve.

[milessw]

Just a safety tip when dealing with Sulfuric Acid especially when it is concentrated...
***Always add ACID to WATER when diluting.***

Adding water to a container with pure or near pure Sulfuric acid is a bit like dropping a Mint in a soda bottle it will boil quite violently and go everywhere..

[squiggy2]

here here!

[gauzz]

That's exactly what I was looking for. I don't want to extract the oxigen to breath it, just want to be safe :)

[maestrocaldwell]

Just be careful of NaOH in high concentrations. It's a strong base, and at high concentrations it can melt your skin.

[gauzz]

One question. Is it possible to remove the water bridge and place a wire or conductor instead? To isolate better hydrogen and oxigen.