The beaker because one change. The electrons from the metal (zn) to the solution (cu) when in contact with solvents, metals zn cu zn metals to be eroded until it turns black and the beaker 2 3 4 unchanged.
Conclusion beaker that 1 changes because. The transfer of electrons from the lo (Zn) to the solution (Cu) when in contact with the metal Zn solution Cu makes metal Zn is corrosive to turn black beaker 2 3 and as 4. There is no change.