Good day.

Applying DC to electrodes in saline water; what disassociates / separates / deposits first on them, as voltage rises ? 

The hydrogen and oxygen; or chlorine and sodium ?  What determines which go first ?   Salt is already ions in suspension, right ?   Or becomes hypochlorite / hypochlorous acid ?

Hydrogen is always going to be released at the cathode (unless mercury is used as the cathode, in which case sodium is produced dissolved in the mercury). As for what's produced at the anode, whether oxygen or chlorine, I am also curious. I recall that in another thread, @exchemist said that both are produced, depending on the chloride concentration.