Electrolysis of Brine: Why Does Castner-Kellner Cell Produce Na?

[DeathKnight]

Electrolysis of Brine...

Why does castner-kellner cell produces Na. I was always told that Na formed too stable an ion to be reduced when it is in aqueous solution even when the solution is concentrated. I myself have carried out this experiment by elecrolysing concentrated aq. Sodium Chloride(Brine) by using a 12V car battery. I could not see any Na formed. If it had formed, I know that it would have reacted with water but if that's the case why couldn't I notice the reaction since Na reacts violently with water?
Thanks on advance for any help...

 

[Borek]

Not sodium is formed, but sodium amalgam, which reacts with water to produce sodium hydroxide. In amalgam sodium is dissolved in mercury so it is not in a direct contact with water.