The chemical reaction in which the one element replaces the other element in a compound is called a displacement reaction. This reaction is also called a replacement reaction.
AB + C -----> AC +B
2ZnS + 3O2 -----> 2ZnO + 2SO2
This happens when A is more reactive than B and gives a stable product. Here the zinc sulfide compound reacts with the oxygen element to the stable product of zinc oxide and sulfur dioxide.
In short, the more reactive element displaces the less reactive element is called a displacement reaction.
