Which products are formed during the electrolysis of a concentrated aqueous solution of sodium chloride?

Question

I. Cl2 (g) II, NaOH (aq) III, H2 (g)

correct answer is all of the above

I need the reasoning

Answer 1

Keeping it basic: The Hydroxyl ion (OH) is negative and bonds with the positive sodium atom (Na).  The Hydrogen gas comes from the splitting of the water molecules into H2 and O.  Oxygen atoms bond with free Hydrogen atoms within the solution to form the OH molecule.  Chlorine, like Hydrogen, is most stable in a pair molecule.