Publisher Summary This chapter briefly discusses the chemical electrochemical techniques. To appreciate electrochemical techniques of chemical analysis, it is necessary to have an understanding of how substances dissociate to form ions. All acids dissociate when added to water to produce hydrogen ions in the solution. The extent to which dissociation takes place varies from acid to acid and increases with increasing dilution until, in very dilute solutions, almost all the acid is dissociated. According to the ionic theory, the characteristic properties of acids are attributed to the hydrogen ions (H+) that they produce in solution. Strong acids (nitric, sulfuric, and hydrochloric) are those that produce a large concentration of hydrogen ions when added to water. Electrical conductivity is discussed with electrical conduction in liquids; there are two classes of substances that conduct electricity. In the first class are the metals and alloys and certain nonmetals, such as graphite, which conduct electricity without undergoing any chemical change. The flow of the current is due to the motion of electrons within the conductor, and the conduction is described as metallic or electronic. In the second class are salts, acids, and bases that, when fused or dissolved in water, conduct electricity owing to the fact that particles known as ions, carrying positive or negative electric charges, move in opposite directions through the liquid. It is this motion of electrically charged particles that constitutes the current. Liquids that conduct electricity in this manner are known as electrolytes.