[Grundalizer]

Hello, I'm working on my inorganic homework and I've come across some questions (I wish I had the book) that I cannot find great answers too from google or wikipedia. 

The question is, in short, why can flourine gas not be produced from electrolysing molten NaF while chlorine gas CAN be produced from electrolysing NaCl? 

At first I figured it had something to do with flourines high electronegativity, and so it perhaps recombined in solution with something else before it combines with itself.  Also, I found out that HF is non-conductive, even though most other acids are.  I'm a little stumped as to where to go with this.

Strange thing is, potassium flouride, KF, works fine for electrolysing, although the steps in which it happens are a little strange.  Forming a biflouride ion or something...

Thanks for the help.