what is meant by displacement and its relationship with the reactivity series?

Answer 1

Displacement basically means that a less reactive atom is replaced by one that's more reactive.

Those higher up in the reactivity series are more reactive,
thus harder to displace,
while those lower down are less reactive,
thus easier to displace.

(Reactivity of the reactivity series decreases down the series)

Answer 2

An element higher in the reactivity series will displace an element that is lower in the reactivity series from a compound. A common example of this is zinc metal, which is higher in the reactivity series of metals than copper; thus, when Zn is added to a solution of CuSO4 (copper sulfate), the Zn will "displace" the Cu from the compound, yielding ZnSO4 and free Cu that precipitates out.

Answer 3

This rxn is impossible as B being larger on pastime sequence (it ability that B has a greater robust tendency to kind compound and react) can not be displaced via A. an factor larger on pastime sequence ability it quite is greater reactive and likes to be in a compound state, so in this reaction B would not get lower back to elemental state from compound state because it quite is greater reactive than A