Question

what what will happen if copper wire is dipped in iron II sulphate solution​

Answer 1

No reaction will take place.

This is because copper can't displace iron from it's salt solution since it is less reactive than iron.

Answer 2

Oxidation reaction may be endothermic or exothermic depend upon the nature of reactant

Those oxidation reaction in which reactant are highly reactive give exothermic reaction.

Exothermic: combustion of hydrocarbons, thermite rxn, burning a reactive metal for example sodium in air.

Endothermic: burning a nitrogen in air.

nitrogen is very less reactive so its oxidation become endothermic.