On this reduction potential chart, the elements that have the most positive reduction potentials are easily reduced and would be good oxidizing agents (in general, the nonmetals), while the elements that have the least positive reduction potentials are easily oxidized and would be good reducing agents (in general, metals). Let’s try a quick problem.

 

 

    Which of the following elements would be most easily oxidized: Ca, Cu, Fe, Li, or Au?

 

 

    Use the reduction potential chart: nonmetals are at the top and are most easily reduced. Metals are at the bottom and are most easily oxidized. Lithium is at the bottom of the chart—it’s the most easily oxidized of all. So the order, from most easily oxidized to least easily oxidized, is Au, Fe, Cu, Ca, Li.

 

 

    Which one of the following would be the best oxidizing agent: Ba, Na, Cl, F, or Br?

 

 

    Using the reduction potential chart and the fact that oxidizing agents are the elements that are most easily reduced, we determine fluorine is the best oxidizing agent.

 

    Electrolytic Cells

 

    While voltaic cells harness the energy from redox reactions, electrolytic cells can be used to drive nonspontaneous redox reactions, which are also called electrolysis reactions. Electrolytic cells are used to produce pure forms of an element; for example, they’re used to separate ores, in electroplating metals (such as applying gold to a less expensive metal), and to charge batteries (such as car batteries). These types of cells rely on a battery or any DC source—in other words, whereas the voltaic cell is a battery, the electrolytic cell needs a battery. Also unlike voltaic cells, which are made up of two containers, electrolytic cells have just one container. However, like in voltaic cells, in electrolytic cells electrons still flow from the anode to the cathode. An electrolytic cell is shown below.