8 hours ago, Moontanman said:

I've done the electrolysis of salt water, it was more or less full strength seawater, all I got was sodium hydroxide and chlorine, I'm not sure what I did wrong, it's been 45 years since I did that, my memories of the salt percentage might be off. I'll go with your assessment. 

You're not wrong, it's just that you've forgotten about the hydrogen:-

 2Cl⁻(aq) -2e⁻ -> Cl₂(g) ; 2 H₂O(l)+ 2e⁻ -> H₂(g) +2OH⁻(aq)

So the hydroxide anion takes the place of the chloride anion that has been converted to chlorine gas, i.e. NaCl is progressively converted to NaOH. But with evolution of both chlorine and hydrogen.

As @TheVat says, at higher dilutions there is competition from direct electrolysis of the water itself.

 

5 hours ago, exchemist said:

You're not wrong, it's just that you've forgotten about the hydrogen:-

 2Cl⁻(aq) -2e⁻ -> Cl₂(g) ; 2 H₂O(l)+ 2e⁻ -> H₂(g) +2OH⁻(aq)

So the hydroxide anion takes the place of the chloride anion that has been converted to chlorine gas, i.e. NaCl is progressively converted to NaOH. But with evolution of both chlorine and hydrogen.

As @TheVat says, at higher dilutions there is competition from direct electrolysis of the water itself.

 

I'm not sure I understand, shouldn't sodium hydroxide should be in the result? 

Just now, Moontanman said:

I'm not sure I understand, shouldn't sodium hydroxide should be in the result? 

Eh? That is what I wrote:”NaCl is progressively converted to NaOH”.

8 hours ago, exchemist said:

Eh? That is what I wrote:”NaCl is progressively converted to NaOH”.

I missed that, evidently I need to relearn the periodic table, sorry