What are oxidation reduction reactions in chemistry?
Oxidation-reduction is the name given to any reaction that occurs by means of the transfer of electrons between reacting substances.
They are also known as "redox" reactions. In this type of reaction:
One substance will be the donor of electrons. The loss of electrons by a substance is called oxidation.
An example of oxidation would be the change of any metal into (positive) ions:
Another substance must be present to acquire these electrons. The gain of electrons is called reduction.
An example would be the change of chlorine gas into chloride ions:
There is no "typical" type of reaction that is an oxidation-reduction reaction - they include combustion of fuels, but also the action of bleach and antiseptics. The reactions that power batteries are redox reactions as well. So, they span a very wide range of different types of reactions that all occur because of electron transfer.