[1] Electrochemistry | Electrolytic cell | Electrolysis | Cell Potential | BSc, MSc, Net, IIT JAM

Electrochemistry is a branch of physical chemistry that studies the relationship between electrical parameters and the identifiable chemical changes, with electricity considered as an outcome of a particular chemical change.

Oxidation and Reduction Reactions

In a large and important class of reactions we find it useful to focus on the transfer of one or more electrons from one chemical moiety to another. Reactions in which electrons are transferred from one chemical moiety to another are called oxidation–reduction reactions, or redox reactions, for short.

Electric Potential

Electrical potential is measured in volts. If a system comprising one coulomb of charge passes through a potential difference of one volt, one joule of work is done on the system. Whether this represents an increase or a decrease in the energy of the system depends on the sign of the charge and on the sign of the potential difference.

Electrolysis and Faraday

Electrolytic cells are very important in the manufacture of products essential to our technology-intensive civilization. Only electrolytic processes can produce many materials, notably metals that are strong reducing agents. Aluminum and the alkali metals are conspicuous examples. Many manufacturing processes that are not themselves electrolytic utilize materials that are produced in electrolytic cells. These processes would not be possible if the electrolytic products were not available.

Oxidation State

The definition of oxidation states predates our ability to estimate electron densities through quantum mechanical calculations. As it turns out, however, the ideas that led to the oxidation state formalism are directionally correct; atoms that have high positive oxidation states according to the formalism also have relatively high positive charges by quantum mechanical calculation.

Electrolytic and Galvanic cell

The difference between electrolytic and galvanic cells lies in the direction of current flow and, correspondingly, the direction in which the cell reaction occurs. In a galvanic cell, a spontaneous chemical reaction occurs and this reaction determines the direction of current flow and the signs of the electrode potentials. In an electrolytic cell, the sign of the electrode potentials is determined by an applied potential source, which determines the direction of current flow.