Answer: Electrochemistry is a branch of chemistry that studies the changes that cause electrons to move and the movement of electrons is called electricity. Electricity can be generated in electrochemistry by movements of electrons from one element to another in a reaction known as a redox reaction or oxidation-reduction reaction.
A redox reaction involves a change in oxidation state of one or more elements. When a substance loses its electron then it is called oxidized and if it gains an electron then it is reduced. For example, for the redox reaction:
Rewrite it as
Overall Reaction: H2+F2→2H++2F−
In the above example H2 is being oxidized, while F2 is being reduced.