Question

what do mean by displacement reaction

Answer 1

The reaction in which an atom or a group of atoms in the molecule is displaced by another atom or a group of atoms is called displacement reaction.

Answer 2

Displacement Reaction-
A reaction in which the more reactive element displaces a less reactive element in a compound. Non metals take part in these types of reactions.
CuSO4+ Fe------> Cu + FeSO4
It is a common example.