Colour change occurs during electrolysis of water?

[karthiloves]

i have done electrolysis of water, during the process colour change occurs . What is the inference for the colour change?

i used steel foils as electrodes, H2O as electrolyte.

Since water is low conductor of electricity, so i added NaCl (Salt crystals) to enhance the electrolysis process.

whether the steel would have undergone any reaction with water or the salt i have added to enchance the electrolysis process would have reacted with the steel electrode.

[Hix3r]

Now this is an interesting one. You wanted water electrolysis, now you got something else.

Now when you added NaCl, the reaction on the cathode changed. On normal water electrolysis the cathode produces O2, the anode H2. Now with NaCl added, anode H2, cathode Cl2. Anyway you can pretell this by looking at the standard electrode potentials. The electrolysis of water to H2 and O2 has -0.84, or so, and chloride forming chlorine is a positive value. Here always the positive goes first. On the anode Na+ forming Na has -verymuch, so there is no problem.

Now the chlorine has a greenish, yellowish color to begin with. With steel it can produce Fe(II)Cl2, which in solution has a greenish color! So your solution had these.

Steel for anode and cathode is probably not such a good idea. Try using graphite electrodes! You can buy these batteries which were used long ago, have the size of a half a dollar bill. In there there are graphite rods. I tokk one apart, pulled out two of these, attached cables, and there we go.

If you want to strictly want water electrolysis, you might want to add Na salts which have SO4 or NO3 attached to them. So NaNO3, Na2SO4, because these more complex ions will never take part in electrolysis in water solution. I would recommend nitrates because they have extremely good solubility. KNO3, this is just as good.