What is displacement reaction
1. What is displacement reaction
A displacement reaction happens when a more reactive element replaces a less reactive element in a compound.
General pattern: Element A + Compound of B and C → Compound of A and C + Element B.
2. Why It Happens
Elements have different reactivities.
A more reactive element can push out a less reactive one.
A less reactive element cannot replace a more reactive one.
3. Types of Displacement
3.1 Single Displacement
One element replaces another element in a compound.
Example:
Zinc + Copper sulfate → Zinc sulfate + Copper
3.2 Halogen Displacement
A more reactive halogen replaces a less reactive halogen.
Example:
Chlorine + Potassium bromide → Potassium chloride + Bromine
3.3 Double Displacement
Two compounds exchange ions.
Example:
Silver nitrate + Sodium chloride → Silver chloride + Sodium nitrate.
4. Reactivity Series (Important Tool)
Potassium
Sodium
Calcium
Magnesium
Aluminum
Zinc
Iron
Lead
Hydrogen
Copper
Silver
Gold.
5. How to Predict a Reaction
Check the free element.
Compare its position in the reactivity series.
If it is higher in reactivity, the reaction will happen.
If it is lower, the reaction will not happen.
6. What You Can Observe
Color change
A solid metal forming
Formation of a precipitate
Temperature change