Reactions
Displacement reaction — প্রতিস্থাপন বিক্রিয়া
Quick answer
In a displacement reaction a more reactive element takes the place of a less reactive one inside its compound.
Definition
A displacement reaction happens when a free element, being more reactive, pushes a less reactive element out of its compound and takes over the vacant place. Iron dipped in blue copper sulfate solution pushes the copper out: Fe + → + Cu, and the blue fades as red-brown copper settles on the iron. The reactivity series tells you at a glance which displacements work: metals above hydrogen can push it out of dilute acids, while copper, sitting below hydrogen, cannot.
For example
Drop a clean iron nail into copper sulfate solution in the school lab and it comes out copper-plated, while the solution turns from blue to pale green iron sulfate.