Electrochemistry encompasses chemical and physical processes that involve the transfer of charge.

Some examples are electroplating, iron oxidation (rusting), solar-energy conversion, energy storage (batteries), photosynthesis, and respiration

In chemical reactions, if the reaction is driven by an external applied voltage, as in electrolysis, or if a voltage is created by a chemical reaction as in a battery, it is an electrochemical reaction. Chemical reactions where electrons are transferred between molecules are called oxidation/reduction (redox) reactions. In general, electrochemistry deals with situations where oxidation and reduction reactions are separated in space or time, connected by an external electric circuit to understand each process.

There are two categories of electrochemical processes that are applied to quantitative measurements:

   1. potentiometry - measurement of a potential (voltage)

   2. electrolytic methods - measurement involving a current

In both of these categories, an electrochemical measurement can be related to the concentration of an analyte