Answer to Question #149607 in General Chemistry for Nico

Question

Describe the differences in the electrolysis of dilute and concentrated sodium chloride solution using inert electrodes.

Answer 1

In the electrolysis of dilute $NaCl$, water is prevalent and the result is hydrogen yielded at cathode and oxygen at the anode.

However, in the electrolysis of concentrated $NaCl$ solution, hydrogen gas forms at the anode, chlorine gas forms at the cathode, and a solution of NaOH forms.

This is because the concentration of the various species regulates the behavior. When in a dilute solution, hydroxyl ions predominates, so production of oxygen predominates but in a concentrated $NaCl$ solution, chloride ions dominates and therefore production of chlorine becomes dominant.