Jump to content

Water electrolysis in the kitchen


FreshMadEagr

Recommended Posts

Hi,

 

I figured I could try making some H2(g) in my kitchen. Who knows when I will need a source of hydrogen gass :).

 

I attached a couple of wires to a 9V battery (smoke detector type), and put them into a bowl of water. Nothing happened, so I disolved some salt (I guess I should have used normal NaCl for simplicity, but ended up with a mixure of 50% NaCl, 40% KCl and 10% MgSO4, some health version). Surely, bubbles started to appear. After about 10 seconds the battery was running really hot. At first sight I though it worked as planned, but I could only see bubbles from one of the wires. ???

 

I tried putting a lighter flame on top of the water but couldn't notice any difference in the flame. But I guess the amount of H2 produced would not be enough for any noticable difference..??

 

Comments?

Link to comment
Share on other sites

Watch out, you are also producing chlorine gas!

 

Shit.. :cool: But I'm alright, didn't even smell anything. But thanks for telling me :embarass:

 

Any suggestion on how to increase conductivity in the water without the unfortunate chlorine gas ? Only got one 9V battery here, and nothing besides typical household items.. home with the flu

Link to comment
Share on other sites

Sure, I will just go and take the battery out of my parents' car!

 

I am also under the impression that car batteries aren't that cheap.

 

There aren't even hicks with their cars up on blocks waiting for the battery to be stolen around here.

Link to comment
Share on other sites

Hence the use of vinegar. Heck, even baking soda would work. You just need something that will dissolve in water and form ions. Na2CO3 will readily dissolve in water and conduct a charge so the electrolysis will happen just fine.

Link to comment
Share on other sites

Best electrolyte for producing H2 is solution of NaOH. You need concentrations less than 10%.

 

Whatever you use you need lot of current to make any reasonable quantities of gas. Faradays Law says that 28.7 ampers of current must flow through electrolyte within one hour to move one gram-molecule of H+ ions to the negative electrode. Its not very realistic with ordinary battery even regrading that you may use 10 times less of current if it flows within 10 hours.

 

Its good if voltage on electrodes is keept as low as possible because anything that is higher than some volts is useless for electrolysis and will just heat your solution up. Also beware that hydrogen tends to form explosive mixtures with air!

 

Chlorine (if you use chloride electrolytes) is not particullary dangerous because its smell is so nasty. In case you want to get chlorine, strong currents are even more essential because first grams of it will dissolve in water. This is reason why you did not see bubbles on one of electrodes.

Link to comment
Share on other sites

foil, which would explain the Al203 which i prosumed was the gooy stuff.

 

Im to tired to think of chemistry at the moment, but i prosume the reactivity of Al compared to H has something to do with it?

 

Unfortunatly then the fuse blew in the plug, so no more was made :-(

Link to comment
Share on other sites

Best electrolyte for producing H2 is solution of NaOH. You need concentrations less than 10%

 

How would this work? I thought that when you used NaCl one of the products was NaOH, so wouldn't you just have the southern cation swap going on?

Link to comment
Share on other sites

You might want to take apart some batteries to get the carbon rods in the center to use as electrodes, because if you use copper or iron electrodes, they can react with the oxygen produced to make copper or iron oxides which muck up the solution (which may also be why you only get one stream of bubbles, the oxygen is reacting with the electrodes). The carbon should be relatively nonreactive, at most making CO2 which is a gas and therefore not going to muck up the solution.

Link to comment
Share on other sites

I think that Na+ goes to negative electrode, reacts with water (as you expect of sodium) and releases H2 and with this also changes back to NaOH. On positive electrode excess OH- ions probably release some oxygen to make H2O again. I supose it is something like that, but theory is not my strongest point. But solution of NaOH is best of all electrolytes i have experimented with. No byproducts are formed, amount of NaOH will not decrease with time, electrical conductivity is better than with NaCl or H2SO4 and any kind of stainless steel can be used as electrodes with no corrosion or dissolving of electrode material. You can try it yourself.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.