Question 6

[eo5]

How is NaCl separated? Wouldn't Na+ (from NaCl) form into Na and Cl- form into Cl2 to separate the two? If that was the case than it would have -4.07V.

[admin]

In a standard electrolytic cell with molten NaCl: as you mentioned, Na solid and Cl2 gas are formed and the voltage is -4.07 which suggests that energy is required for the reaction to occur.

However, the question is asking about the reverse reaction. How is sodium and chlorine (Cl2) separated which suggests ionizes. The opposite reaction (separating into ions) would be +4.07.

[admin]

However, both reactions are not spontaneous. A reaction must have a positive Eo to be spontaneous. A galvanic cell will only function if the reaction occurs spontaneously (positive Eo).

The classic reaction that you are accustomed seeing (Cl2 gas and solid Na plating) is for an electrolytic cell which is driven by a battery. Because galvanic cells (=electrochemical cells) create energy and electrolytic cells require energy, they are often considered opposites.