Electrolytic and voltaic cells

Electrolytic and Voltaic Cells

An electrolytic cell is a cell that is made up of two electrodes touching an electrolyte and that causes a chemical reaction when connected to an external source of electricity. The electric energy is used to decompose chemical compounds and the process is referred to as electrolysis, this leads to an increase in the chemical energy. This cell has three major components, the electrolyte, an anode, and a cathode. The anode and cathode are usually referred to as electrodes. The electrolyte is normally water solution or any other solvent that ions can dissolve in example being salts like sodium chloride. The application of external voltage to the electrodes makes the electrolyte to produce ions which flow to and from the electrodes where redox reaction takes place. The applied electrical energy reverses the effect of impulsive chemical reactions.

A voltaic cell is a device that converts chemical energy into electric energy this it does by deriving electrical energy from the chemical reactions that take place within, it is also referred to as an electrochemical cell. This device is made up of two distinct metals linked by a salt bridge or single half-cells separated using a porous film. Every half-cell consists of a metal and a salt solution corresponding to the metal. In the salt solution is contained the metal's cation and an anion to bring balance on the cation's charge. Basically the half-cell has the metal in two oxidation states and the type of reaction that takes place within it is redox reaction. In this cell, one metal is capable of reducing the cation of the other; on the other hand, the first metal can be oxidized by the cation. There is need to avoid the mixing of the two half-cells thus they must be physically separated. The quantity of electrons transferred in either direction must be equal thus combining the two half-cells gives the whole-cell electrochemical reaction. Therefore, to get the voltage of the cell, the voltages of the two half-cells are added.

Therefore, the contrast that exists between electrolytic cells and voltaic cells is that whereas the former uses electrical energy to trigger a chemical reaction the latter derives electrical energy from a chemical reaction. This means that their operation is totally opposite in direction, in fact a rechargeable battery can act as both a voltaic cell and an electrolytic cell depending on whether it is discharging or being charged. It is also practical to use the same type of metal as electrodes in an electrolytic cell while in voltaic cells the electrodes must be of different metals.