Define displacement reaction. Give two examples of it. How it is different from a double displacement reaction.

The reaction in which an atom or a set of atoms are displaced by another atom in a molecule is called displacement reaction. For instance, when Iron is added to a copper sulfate solution, it displaces the copper metal.

A + B – C → A – C + B

The above equation exists when A is more reactive than B.

The reaction in which two atoms or a group of atoms are displaced by another atom in a molecule is called a double displacement reaction.

A-B + C-D → A-C + B-D

A and B have to be either:

• Halogens where C indicates a cation.
• Different metals wherein C indicates an anion.