What Is Electrochemistry?

Electrochemistry is a branch of chemistry that involves the study of chemical reactions dealing with electric energy and chemical changes. The chemical reactions in which either electric current is produced or is required for the reaction to occur are called Electrochemical reactions. 

Examples of Electrochemistry:

• The most common example of electrochemistry is a battery which we use in day to day lives. A normal battery that is used in toys, torches, etc. is made up of chemicals. These chemicals react within the cell and produce an electric current that is used by us. Once all the chemical inside the cell is used up in the reaction, it becomes dysfunctional. Nowadays, a better version of these throw-away batteries is available- rechargeable batteries. Rechargeable batteries can be used again and again after a certain amount of charging. There are different examples of this – car batteries, laptop batteries, mobile phones, etc.
• Also, many household products are a result of electrochemistry. Bleachers made from Chlorine and caustic soda by brine electrolysis. Also, it can be directly made from electrochemical cells.
• Electrochemistry is used to extract many metals from their res such as aluminum, copper, zinc. Silver, lead, etc. 
• The decorative coatings on many utensils and jewelry items are done by using electrochemical plating. 
• Electrochemical techniques can also be used to prevent things from corrosion. 

Principles in Electrochemistry

Reduction oxidation reactions also called redox reactions are electrochemical processes that involve electron transfer either to or from an ion so that the oxidation state of the molecule changes. Redox reactions are initiated by the application of external voltage or by releasing chemical energy. Oxidation and reduction describe the change in the oxidation state of the atoms, ions, or molecules. The loss of one or more electrons from a molecule is called oxidation and the gain of one or more electrons in a molecule is called a reduction. The atom or the molecule that loses electrons is called the reducing agent and the atom or the molecule that gains electrons is called the oxidizing agent. The oxidizing agent gets itself reduced and the reducing agent itself gets oxidized. 

The Concept  of an Electrochemical Cell 

An electrochemical cell produces electrical current by the energy released in a redox reaction. An electrochemical cell has two electrodes – Cathode and Anode. Oxidation occurs at the anode and reduction occurs at the cathode. In between the cathode and anode, there are electrolytes that contain free ions. To complete the circuit, there must be an ionic conduction path in between the electrodes. This is fulfilled by a liquid junction. As there is a risk of the electrolyte and the liquid junction getting mixed, the liquid junction is poured through a porous plug. To avoid the mixing of the electrolytes, a salt bridge is used that contains an electrolyte saturated gel in a reverse U-tube. The negatively charged ions flow in a single direction and the positively charged ions flow in the direction opposite to the electrolyte. A voltmeter measures the difference in electrical potential between the electrodes. The voltage of an electrochemical cell is called an Electromotive Force (EMF).

Concentration cell

An electrochemical cell that contains the electrodes of the same material, the electrolytes on the half cells also contain small ions, the only difference being in the electrolyte concentration is called a concentration cell.

Applications of Electrochemistry

There have been many useful applications of  Electrochemistry:-

• Most of the metals except iron and steel are refined by electrochemical processes. For eg- aluminum, titanium, copper, etc.
• With the help of electroplating, corrosion, as well as the decoration of various metals, is possible. This has been really helpful in big industries such as automobile industries which need corrosion-free metals in their vehicles.
• Many modern devices run on batteries and in the absence of electrochemistry, it would not have been possible to operate them. The nickel-iron cell or the Edison cell and the nickel-cadmium batteries embedded in these system switches need to function for longer hours. Also, the silver-zinc batteries are used to start airplanes because of their high power per unit of weight.
• Fuel cells are another example of electrochemical cells where any fuel (like hydrogen, hydrazine) is fed to one end of the electrode while oxygen present in the air reacts with the other electrode. 
• Electrochemistry is applicable in analytical chemistry where most automated instrumental analysis is based on electrode processes.
• There have been various things in biology that are linked to the concept of electrochemistry.