1. An electrolytic cell uses electricity to do a chemical reaction.
Electrochemistry
An electrolytic cell uses electricity to do a chemical reaction.

2. An Electrolytic Cell
The negative terminal of the battery forces electrons to the attached electrode.
The electrode becomes negative.

3. An Electrolytic Cell
The positive terminal of the battery draws electrons out of the attached electrode.
The electrode becomes positive

4. Electrolysis Apparatus
The two electrodes are placed in an electrolyte solutions such as NaCl(aq) to allow the electrons to flow.

5. Electrolysis
The sodium ions (Na+) are attracted to the negative electrode.

6. Electrolysis
The Na+ is reduced to a sodium atom because it gains an electron.
Na+ + 1e-  Na

7. Reduction at the Cathode
Na+ + 1e-  Na
This ½ reaction is called REDUCTION and it occurs at the CATHODE

8. Electrolysis
The chlorine ions (Cl-) are attracted to the positive electrode.

9. Electrolysis
The Cl- is oxidized to a chlorine atom because it loses an electron.
Cl-  Cl + 1e-

10. This ½ reaction is called OXIDATION and it occurs at the ANODE.
Oxidation at the Anode
Cl-  Cl + 1e-
This ½ reaction is called OXIDATION and it occurs at the ANODE.

11. Oxidation and Reduction
REDUCTION Na+ + 1e-  Na
OXIDATION 2Cl-  Cl2 + 2e-
(Chlorine is diatomic, so it is different)
To finish this reaction, multiply the top equation by 2 so you will lose 2 electrons and gain 2 electrons.

12. Final Equation 2Na+ + 2e-  2Na 2Cl-  Cl2 + 2e-
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2Na+ + 2Cl-  2Na + Cl2