Expert: Labman - 2/14/2005

Question
Do You know anything about this? Also known as Splitting Water. It is a science project I am doing for fun! But I do not know how it works. the Site I got it off of is www.energyquest.ca.gov/projects/split_h2o.html

Answer
Most of the hydrogen and oxygen in water are bound together in molecules, sharing electrons, and not having any charge.  A very small amount of the water breaks down into charged particles called ions, H3O+ and OH-.  The total of the 2 is always 0.00000000000001 per liter, more conveniently written 10^-14.  If there are equal numbers then there will be 10^-7 H3O+ ions, pH 7, a neutral solution.  

If you place conductors in water and pass an electric current through them, any positively charged ions will go to the negative electrode and negative ones to the positive one.  At the cathode, the least active ion will accept an electron losing its charge and becoming an atom or molecule instead of an ion.  Most metals will plate out.  Otherwise the H3O+ ions will accept an electron turning into a molecule of water and an atom of hydrogen.  The atoms of hydrogen will quickly join to form H2 molecules and bubble up out of the solution.  More water will break down into ions to maintain the 10^-14 total.  

This is an important source of chemicals, but will never be a source of energy, because it takes as much energy to prepare hydrogen as it gives off when oxidized.  Most of the hydrogen used today is make from natural gas because it is cheaper then electrolysis.