A single replacement reaction (also called a single displacement reaction) is a type of chemical reaction in which one element replaces another element in a compound. In this process, a more reactive element takes the place of a less reactive element.
For example:
- A metal can replace another metal from its compound (usually in an ionic solution).
- A nonmetal can replace another nonmetal, commonly halogens.
This type of reaction generally follows the idea that the replacing element must be more reactive than the element it replaces. If it is less reactive, the reaction will not occur.
Example:
When zinc is placed in copper sulfate solution, zinc replaces copper because zinc is more reactive:
Zinc + Copper Sulfate → Zinc Sulfate + Copper.
In short, a single replacement reaction occurs when one element “kicks out” another from a compound.