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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!
<p>it is possible to obtain petrol from hydrogen?</p>
<p>petrol, or petroleum by-products, are chemical chains of carbon and hydrogen. For this reason, they are all called hydrocarbons.</p><p>So, yes, you CAN build petrol from hydrogen and carbon, however, it takes energy to do so. Burning hydrogen directly, in combination with atmospheric oxygen, derives plenty of energy without going through the extra steps, waste, and expense to make more complex molecules.</p><p>The real problem with hydrogen is the difficulty of storing it. The molecules are so small and slippery, they tend to leak out any container you put it in. And making it dense enough to make carrying it portable for long trips is a further complication.</p>
<p>Ok, so I am making a remote controlled blimp, and need to make hydrogen for the lift gas. is there any way to pressurize the hydrogen so it goes through the tube and into the blimp?</p>
Maybe a vacuum pump and an old spray can could do the trick, you could control it with an arduino.
<p>Hi I was wondering as this would be my first try at something like this would this work?</p><p>a 9v battery, a plastic bowl, two 0.9 sticks of mechanical pencil graphite, two plastic test tubes to turn upside down on top of the graphite, and just some copper wire i have stripped from various electronic components to tie around the graphite and the correct charges on the battery?</p><p>Also do the test tubes that in my case that would be on top of the graphite, do they need to be partially submerged in the water as well as shown in step 5?</p><p>And if all this is true i just let it sit on there and connect it to the battery let it run for a bit then have hydrogen and oxygen?</p>
<p>yes, but make sure to insulate the copper wires or they will corode. </p>
<p>ı have a question, i did this project with an ATX power supply on 12 volts and i didnt try to collect the hydrogen or oxygen. I let it run for 10 minutes but later I realized that something green is formed in water. What is it and how can i dispose it?</p>
<p>if you have copper wires it's the bits of corroded copper i think or i might be wrong. Don't use copper wire as a electrode, it does not last too long. aluminum turns this weird gray color for me. p.s. this is also how electroplating works!</p>
can anybody share the video plz???
<p>wouldn't using graphite/carbon electrodes create CO2/CO as they erode? that's what happens when electrolysing aluminium (as far as I know)</p>
<p>An interesting article - thank you - though the comments are possibly more entertaining albeit for the wrong reasons :)<br><br>I would go along with suggestion of replacing the table salt with something else - and providing folks are careful, would suggest caustic soda while caustic (really?) is the best choice as other than sodium, it contains nothing more than oxygen and hydrogen.<br><br>Unless it acts purely as a catalyst and just &quot;hangs around&quot;, I am guessing that baking soda may be adding carbon in the form of CO2 to the gas produced.<br><br>I may be wrong on that, but certainly sodium hydroxide will NOT contribute ANYTHING as a contaminate.<br><br>As for the HHO generators, I find valid points on both sides, in the first case, clearly generating the gas from an engine&gt;alternator&gt;battery power source is not going to yield more energy that is consumed in making it - so really not a fuel, more an inefficient conversion of one type of chemical energy into another - BUT I do believe it MAY be beneficial particularly on older cars.<br><br>The more out of sorts the engine is, the more I am guessing a whiff of something extremely volatile may be of benefit - even if the amount of gas added is totally insignificant from a &quot;fuel&quot; point of view, possibly it does assist in enabling a more efficient burn of the vapourised petrol. This could improve performance and economy while reducing emissions.<br><br>In much the same way that OLDER engines often seem to do rather well on LPG though a more moder efficient engine doesn't seem to yield a similar benefit (in both cases of course, LPG has a lower BTU than petrol but in older cars, results often seem to be better than optimal - which is almost certainly down to the fact that the old engine was struggling to burn the petrol/gasoline air mixture as efficiently as it was suppoed to - the lpg however provided an &quot;easy more efficient combustion&quot;.)<br><br>So, I suspect an HHO generator may be of benefit on an older, tired engine with poor / fouled injectors etc or during VERY cold temperatures where the conventional fuel really is not being burned as well as it should be - the HHO gas may simply assist slightly in the volatility - as well as enabling the engine to run VERY slighlty leaner by adding a stochiometric mix to one which is normally kept rich. The more gas added, the closer to a stochiometric mixture, the leaner the burn. (I would expect a decrease in CO but an increase possibly in Nx ?)<br><br>In much the same way, that TINY amounts of acetone in a new car seem to do NOTHING at all of use (as you might expect as it has a lower BTU than regulalr petrol (gasoline) - yet in an old car, can sometimes make for a cleaner burn - nothing magical I suspect other than simply lowering the flashpoint slightly and making the fuel marginally more volatile?<br><br>Quite happy to be challenged on the above but you don't need to tell me how many reciepts you have for education (sorry, I mean degrees), just make a fair and reasoned point, I am keen to learn when I am wrong - but I have learned just as much from people who make &quot;happy mistakes&quot; and go &quot;oh wow, that's interesting&quot;, than the people who aim never to make mistakes.</p>
<p>think you may have the positive and negative terminals around the wrong way.</p>
My goodness I feel like I lost two years off my life from all that arguing. Your wrong no your wrong no ones wrong no we're all wrong who cares it's all in the name of science just learn from others mistakes as well as your own and aim for the greater good! and to think such a nice instructable became a battleground for talk about nuclear submarines and theoretical car enhancements that have already been made, and no I will not be arguing with anyone who says that nuclear submarines are a myth or that the government will kill us all for experimenting with alternate energy. Future comes even if your mad about it. Sticks and stones people. Sticks and stones.
<p>I'll second the production of hydrogen and chlorine gasses with table salt (sodium chloride). It has to do with the preference of half-reactions. See the Wikipedia article for &quot;Electrolysis of water&quot; for details. Sodium hydroxide, a.k.a. lye, would apparently work very well, but of course, that's caustic and therefore somewhat dangerous. Sodium bicarbonate (baking soda) will work OK as others have suggested.</p>
<p>I dont wanna divert the topic, but you can charge your blood with oxygen using food grade Hydrogen peroxide diluted to 3% in distilled water and drink it.</p>
<p>Internet says average person consumes 3.15 <br>mL. of oxygen per kilogram of body mass each minute while asleep.</p><p>8hours=480minutes</p><p>480minutes*3.15ml=1512ml~1.5lt</p><p>1.5lt*kg/night</p><p>for 50KG=75L/night</p><p>for100KG=150L/night</p><p>120 scfh O2 requires 1050 <br>ADC(2 or 12V?)</p><p>SCFH = standard <br>cubic feet per hour<br>35cubic feet=0.99109cubic meter</p><p>@~1000A------------------------------------------<br>120cubicfeet/hour=3.39802cubic <br>meter/hour ~3.4cubic meter/hour<br>3.4*8hours=27.2 cubic <br>meter/night<br>~30cubic meter/night<br>---------------------------------------------------------</p><p>for50KG person<br>75/30=2.5X simply means it needs 2500Ah</p><p>for100KG person<br>150/30=5X simply means it needs 5000Ah<br><br>So according to this, you can't even replace what you breathe at night.<br></p>
<p>I would not advise breathing the Oxygen generated by electrolysis of water:</p><p>1) Unless it is separated from Hydrogen, even then it may contain 20% Ozone for the first 30 minutes.</p>
<p>You divided liters by cubic meters there. One cubic meter == 1000 liter. So your result is off by a factor of 1000.</p>
<p>Damn! you are right! How did I make such stupid mistake?!<br><br>then if werecalculate it:<br>@ 1000A<br>30cubic meter= 30000lt/night<br><br>for 50 KG person<br>75/30000=0.0025Ah=2.5mAh or<br>30000/75=400 nights<br><br>For 100KG person<br>150/30000=0.005Ah=5mAh or<br>30000/150=200 nights<br><br>so,<br>for 1 night for 100KG person:<br>1000A/200nights=5A/night is enough!<br>but then the question is:<br>How many Volts?</p>
Can I use an engine's gas tank (lawnmower) as the hydrogen reservoir? How would I collect the hydrogen directly in the gas tank?<br><br>Can I hook up a motor to the driveshaft of an engine to generate the electricity instead of a battery?<br><br>Does hydrogen require oxygen to burn?<br><br>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?
<p>No, you cannot use the gas tank as a 'reservoir' because of the danger of flashback.</p><p>Yes, Hydrogen requires Oxygen to burn.</p><p>2 Volts are required to split a water molecule.</p><p>Amps determines the speed of electrolysis.</p><p>Take a glass of water, stir in a teaspoon of baking soda then drop in a 9 volt battery. Hydrogen bubbles will stream up from the Cathode(-) post and Oxygen bubbles will stream up from the Anode(+) post.</p>
<p>yes! hydrogen need an amount of oxygen to combust.</p><p>i think greater amperes has a greater extraction of hydrogen. </p>
Yes, you can, just fill it with salt water and place it in the container, like you would a test tube. <br> <br>Anything that generates electricity can be used, really. <br> <br>The chemical reaction known as combustion always requires oxygen. <br>2H₂ + O₂ &rarr; 2H₂O + heat <br> <br>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.
<p>I know this post is old and you were a highschooler at the time, but I am impressed that you balanced the equation. On another fun note, I know the Ohio and Virgina class nuclear submarines use this same process to produce breathable air for the crew.</p>
<p>Hi, I just want to point out that your explanation of the electrolysis of water is incorrect. Water is not made up of ions held together by electromagnetic forces. That would be an ionic compound such as salt. Water is a covalent molecule held together by shared electrons in the covalent chemical bonds. During electrolysis, the molecule is reduced at the cathode to hydrogen gas and oxidized at the anode to oxygen gas. That's two different reactions going on, not one single splitting. There is no pulling apart as you describe it to the opposite electrodes. You should really, really edit this egregious mistake. Try this resource for an easier to understand explanation: http://www.nmsea.org/Curriculum/7_12/electrolysis/electrolysis.htm</p>
<p>I always thought that whit electrolysis of salty water you get hydrogen and chlorine gas</p>
<p>Yes, you do. You should never use salt, use baking soda, chlorine is very harmful.</p>
<p>The diagram drawing is wrong. The negative electrode is always called the cathode, &amp; the positive electrode is always the anode. This is an extremely dangerous error because Hydrogen is extremely flammable &amp; explosive. With the contradictory information, an experimenter could easily start a fire or get injured in an explosion. This should be removed until it is corrected so you don't wind up getting sued for injuries.</p>
No, its not. The anode is defined as the location where oxidation takes place, the cathode where the reduction takes place. If this was a galvanic cell you would be right. But this is an electrolytic cell. Do a google search on why if you're curious but this is correct.
<p>Nice project. Keep postin</p>
<p>how to make hydrogen gas not dangerous</p><p>kindly advise</p><p>regards</p><p>Ali</p>
Hydrogen is negative and oxygen positive.
<p>Yes, Dantex is correct. Seems that there are several of these instructables that claim hydrogen comes off the positive (anode), but its the cathode (negative). Someone needs to do their homework before writing these.</p>
Thank you dantex!I was beginning to have a bit of confusion because the diagram appears to be backwards in respect to the anode and diode
<p>Hydrogen bubbles are tiny it's the smallest atom</p><p>Oxygen Bubbles are larger if you don't see Oxygen switch to a pencil lead (Graphite) instead of wires into the fluid.as copper wires will give you a green muss at the bottom of your container as the oxygen leaves with some copper on board for the ride :)</p>
Do you mean their respective charges, or that oxygen comes off the neg. and hydrogen off the pos. ??
When you connect battery in electrolysis you get hydrogen on negative and oxygen on positive.
You're all missing the basics, and blindly following a nut that can't even get the polarity and labels right on a basic circuit will get someone killed! The diagrams above are wrong! Anode should be positive, and H2 comes off at the negative (cathode). Check check check! And be careful.
<p>Yep, he's right. This person did not do their homework, even though he states that the Hydrogen ions are positive, so of course they would be attracted to the negative electrode.</p>
One thing people need to keep in mind with this kind of setup is that you are not going to get the kind of flow required to do any kind of work that will help MPG. These HHO system type things are sold on ebay with plans etc. The amount of work and energy required to get a substantial amount of gas is...substantial. I don't have a degree in physics, but used to run a machine that was designed to make pure O2 for submarines. It required 1050 amps of DC current to produce 120scfh with double that for Hydrogen which we disposed of overboard. The amount of gas produced from a 12 volt source is not enough to help your car. It's a cool science experiment for school, but that's about it. Former MM2(SS) A-gang type. (google what that is. I also used to run the CO2 scrubbers and COH2 burners for atmosphere control.)
1050 amps = about 7 solar panels on a sunny day
Not true. You can't even flow 1050 amps down a regular home wiring because it only handles 20 amps.<br>Go study some more would ya
are you familiar with the inverse relationship between voltage and amperage? I can have a power source that is only a few volts that is 100 amps; or something could put out only a few amps that is 120 volt. Solar panels put out DC current which is typically converted to AC power and manipulated to usable 120volt/15 amp circuits. Your remark &quot;Go study some more would ya&quot; is meant to be inflammatory, and I don't appreciate it...

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