A displacement reaction is a type of chemical reaction in which one element or a set of atoms is displaced by another element or set of atoms in a molecule. In other words, it is a reaction in which an atom or ion in a compound is replaced by another atom or ion. Displacement reactions can be represented generically as A + BC → AC + B, where A is the more reactive element and B is the less reactive element. There are two types of displacement reactions: single displacement reaction and double displacement reaction. Single displacement reaction occurs when one element in a compound is replaced by another element, while double displacement reaction occurs when two compounds react and the cations and anions switch places. Displacement reactions are also known as replacement reactions or exchange reactions.