What is the difference between displacement and double displacement reactions? Write relevant equations for the above.

A displacement reaction occurs when a more reactive substance takes a less reactive one out of its salt solution; a double displacement reaction occurs when two compounds exchange ions.

In a displacement reaction, only a single displacement takes place, whereas, in a double displacement reaction, two displacement takes place between the molecules.

e.g.

Single displacement reaction

Mg + 2HCl → MgCl₂ + H₂

Double displacement reaction

2KBr + BaI₂ → 2KI + BaBr₂