Page 4 - Pharmaceutical Analytical Chemistry II - Pharm D Clinical- 07-PA202

Electrochemical cell

Electrochemical cell is a device that allows oxidation-reduction
reaction to occur, at the surface of the electrodes making up the

cell, by transferring electrons through an external circuit.

Construction of an electrochemical cell

An electrochemical cell consists of: (Anode and

Two conductors "metals" called ELECTRODES
Cathode),

Anode – electrode where oxidation occurs,

Cathode – electrode where reduction occurs

The two electrodes could be assembled in one of the two possible
designs:

Cells without liquid Cells with liquid junctions
junctions
Each of the two electrodes is immersed in an
The electrodes share a common Electrolyte solution and
electrolyte the two electrodes compartments are physically
separated to avoid direct reaction between the
reactants using either porous fritted disk OR salt
bridge (contains sat. KCl solution)

Such a liquid junction allows electrical
conduction between the two electrolyte solutions

E.g. Lead acid battery

3