Question

what is displacement reaction

Answer 1

A single-displacement reaction, also known as a single-replacement reaction, is a reaction by which one element replaces an/other element in a compound. It can be represented generically as: A + B-C → A-C + B This will most often occur if A is more reactive than B, thus giving a more stable product. 

Answer 2

It is form of reaction in which the element with the greater reactivity displaces the element which is less reactive from it's salt.

Here below is the Reactivity series....

\begin{table}[]

\begin{tabular}{|l|l|}

\hline

Potassium & K  \\ \hline

Sodium    & Na \\ \hline

Calcium   & Ca \\ \hline

Magnesium & Mg \\ \hline

Aluminium & Al \\ \hline

Zinc      & Zn \\ \hline

Iron      & Fe \\ \hline

Tin       & Sn \\ \hline

Lead      & Pb \\ \hline

Hydrogen  & H  \\ \hline

Copper    & Cu \\ \hline

Mercury   & Hg \\ \hline

Silver    & Ag \\ \hline

Gold      & Au \\ \hline

Platinium & Pt \\ \hline

\end{tabular}

\end{table}

The displacement reaction take according to this series.

For better understanding, Here are examples of displacement reaction:

1. Fe + CuSO4 → FeSO4 + Cu

In the above example, Iron is more reactive then copper(see the table for reference, so it displaced Copper from it's salt and formed it's own salt.

It is similar to the situation that a strong and rich stranger came into your house, took you out of the house and announced that he is resident of that house.