What exactly is the difference between a concentration cell and galvanic/voltaic cell? How do you know what are the half reactions? Also, is the ion and electron flow the same found in voltaic cells or is it the opposite? My biggest question of electrolysis has to do with Cl species. Here's an example: What appears at the cathode and anode after the electrolysis of SnCl2 I've got this part down: Cathode: Sn2+ +2e =>Sn E: -.14 Water: E:-.83 Anode: 2Cl-=>Cl2 + 2e : 1.36 Water: 1.229 I understand how Sn appears, but why does Cl appear? it has a larger reduction potential meaning it would stand a lesser chance of being oxidized yet for whatever reason every book says that it's more reactive but I don't understand why. Is this the case every time?