There are certain types of reactions in chemistry which take place due to the movement of electrical charges. These electrical charges are transferred between some solid conductor of these electric charges and an ionic conductor. The solid conductor is known as an electrode. It is actually the electrons which constitute the electric charges and their movement takes place at the interface of the electrode and the ionic conductor, which is called an electrolyte.
In electrochemistry, the type of reactions with which we are concerned are redox reactions. Redox reactions are those in which one species undergoes reduction while the other gets oxidized. The process of reduction and oxidation takes place simultaneously and if only the change in one species is shown in the form of a reaction, it is called a half reaction. All the reactions that take place in the field of electrochemistry are redox reactions but not all redox reactions fall under electrochemistry.
Electricity from chemicals
The cells or “battery” that you use to power your RC car’s remote control or the television’s remote control are actually electrochemical devices. When you place the cells between the spring and the plate in your remote control, a circuit is made. The spring and the metallic plate connect the two ends of the cell within an elaborate circuit inside the remote control which allows for a flow of electricity. There is a chemical reaction taking place inside the cell which produces the electrical energy. This electrical energy is utilized by the remote control system to perform the required functions.
Design of the cell
Every electrochemical cell contains two electrodes which are conductive parts of the cell. One of the electrode is called an anode and the other is referred to as a cathode. The oxidation part of the redox reaction in an electrochemical process takes place at the anode and the reduction part at the cathode. Most of the times these electrodes are made out of graphite, an allotrope of carbon, which is a very good conductor of electricity. The electrolyte or the ionic conductor is placed in the space between the two electrodes so that the circuit can be completed when the other two ends of the two electrodes are brought into contact.
Chemical reaction from electricity
Electrochemistry also studies the chemical reactions which take place with the help of electricity. In such a case, the electricity is supplied to the electrochemical system from an outside source and this electrical energy causes the chemical reactions to take place. This process is called electrolysis and the electrochemical system is called an electrolytic cell. Metallurgic industries make extensive use of the electrolysis process. Usually, iron is coated with a protective layer of zinc with the help of electrolysis. Similarly, electrolysis can also be used to purify a sheet of metal. The impure sheet comprises of the anode and the cathode is made out of a thin strip of pure metal. When the circuit is completed and external current is provided, the pure metal from the impure sheet deposits over the pure metal electrode strip. The impurities settle at the bottom and are referred to as anode mud.