Chemistry Revision Notes of Oxidation, Reduction and Electrochemistry for NDA Part-4

Electrochemical Cell

A cell in which spontaneous redox reaction is carried out to produce an electric current is called electrochemical cell.

`=>` An electrochemical cell comprises of two metallic electrodes namely anode [-ve electrode] and cathode [+ve electrode] dipped in electrolytic solution.

`=>` There are two types of electrochemical cell galvanic cell and electrolytic cell.

`=>` In galvanic cell, the chemical energy of a spontaneous redox reaction is converted into electrical energy.

`=>` In electrolytic cells, electrical energy is used to carry out a non-spontaneous reaction.

Electrode

`=>` It is a metal conducting plate (anode or cathode) that emits or collects electrons in a cell.

`=>` Electrode made up of an element with lower reduction potential act as anode. Oxidation takes place at anode. While reduction takes place at cathode.

Electrode Potential

`=>` The potential of an electrode with respect to its solution is called the electrode potential.

`=>` It is a measure of its tendency to lose or gain electrons, when it comes in contact with a solution of its own ions.

`=>` The tendency of all electrode to gain electrons or to get reduced is called its reduction potential.

`=>` The tendency of an electrode to lose electrons or to get oxidised is called its oxidation potential.

It is affected by the following :

(i) Concentration of solution

(ii) Nature of electrolyte

(iii) Nature of metal

(iv) Conditions of temperature and pressure