Redox Reactions refer to a set of chemical reactions which consist of an electron transfer and a change in oxidation state of the reactant species. Redox is an abbreviated term for ‘reduction-oxidation’ reactions, where reduction refers to a gain of electron, while oxidation refers to a loss of electron.
In a reduction reaction, if an atom/molecule gains an electron, then its oxidation state will decrease. On the other hand, in an oxidation reaction, if an atom/molecule loses an electron, then its oxidation state will increase. The following redox reaction can be broken up into a reduction and oxidation reaction:
H_2 + F_2 --> 2HF
H_2 --> 2H+ +2e-
F2 + 2e- --> 2F-
The overall redox reaction then involves the hydrogen transferring two electrons to the fluorine to create an ionic bond between the two atoms and forming the compound hydrogen fluoride (HF). Thus, understanding the basics of reduction and oxidation can help better grasp the complexities of some redox reactions.