When zinc pieces are are put in copper sulphate solution what happens ?

Explanation -
Zinc is more reactive than copper. So, by adding zinc to CuSO4 solution, zinc displaces copper from copper sulphate & forms zinc sulphate solution. This is indicated by colour change from blue to colourless. CuSO4 solution has a blue colour while ZnSO4 solution is colourless.

Chemical equation -
Zn(s) + CuSO4(aq) -> Cu(s) + ZnSO4 (aq).

Type of reaction -

It's a displacement reaction.

It's a redox reaction. Oxidation number of Cu decreases from 2 to 0 so it's reduced. Oxidation number of Zn increases from 0 to 2 so it's oxidised.