4.2 CHAPTER 4. ELECTROCHEMICAL REACTIONS
Uses and applications of the galvanic
cell
ESCBM
The principles of the galvanic cell are used tomake electrical batteries. In science
and technology, a battery is a device that stores chemical energy andmakes it avail-
able in an electrical form. Batteries are made ofelectrochemical devicessuch as one
or more galvanic cells,fuel cells or flow cells. Batteries have many uses including
in torches, electrical appliances (long-life alkaline batteries), digital cameras (lithium
batteries), hearing aids(silver-oxide batteries), digital watches (mercurybatteries) and
military applications (thermal batteries). Referto chapter 5 for more information on
batteries.
The galvanic cell can also be used for electroplating. Electroplating occurswhen an
electrically conductiveobject is coated with alayer of metal using electrical current.
Sometimes, electroplating is used to give a metalparticular properties such as corrosion
protection or wear resistance. At other times, it can be for aesthetic reasons for example
in the production of jewellery. This will be discussed in more detail laterin this chapter.
Exercise 4 - 2
- The following half-reactions take place in anelectrochemical cell:
Fe→ Fe3++ 3e−
Fe2++ 2e−→ Fe
(a) Which is the oxidation half-reaction?
(b) Which is the reduction half-reaction?
(c) Name one oxidisingagent.
(d) Name one reducingagent.
(e) Use standard notation to represent this electrochemical cell.- For the following cell:
Mg|Mg2+||Mn2+|Mn(a) Give the cathode half-reaction.
(b) Give the anode half-reaction.
(c) Give the overall equation for the electrochemical cell.
(d) What metals could be used for the electrodes in this electrochemical cell?
(e) Suggest two electrolytes for this electrochemical cell.
(f) In which direction will the current flow?
(g) Draw a simple sketch of the complete cell.