What is a redox reaction?

A redox (or oxidation-reduction) reaction is a type of chemical reaction that involves a transfer of electrons between two species (atom, molecule or ion). Here oxidation as well as reduction takes place simultaneously. Oxidation refers to the loss of electrons from a substance, while reduction refers to the gain of electrons by a substance. These two processes cannot occur without the other. That being said, if there's a reduction reaction, there must be an oxidation reaction. Or, if there's an oxidation reaction, there must be a reduction reaction. Don't be confused by reduction being a gain, though. Adding electrons is called reduction because the overall charge is reduced - more electrons means the substance becomes more negative. The easiest way to fully understand redox reactions is to look at some examples. So let's start by looking at the reaction that forms table salt. Sodium is oxidized and loses an electron to have a +1 charge; meanwhile chlorine is reduced because it gains the electron to have a -1 charge. The redox reaction creates two ions with opposite charges that are attracted to one another and create sodium chloride, or table salt. At this point it's also important to discuss reducing and oxidizing agents. A reducing agent donates electrons or reduces another substance. So, in the case of our table salt reaction, sodium is the reducing agent. An oxidizing agent accepts electrons or oxidizes another substance. So, in the case of our table salt reaction, chlorine is the oxidizing agent. An oxidizing agent gains electrons, and an oxidizing agent is reduced. read less