Write the equations of possible reactions: CU + HCL → Mg + HCL → Pb + Zn (No₃) ₂ → CU + AgNO₃ →

The possibility of the chemical reactions given in the task is determined by the electrochemical series of metal activity.

Cu + HCI → (the reaction is impossible, since the element copper Cu in the indicated row is after the hydrogen atom H. Hence, it cannot displace it from the solution of the acid HCI).

Mg + 2 HCI → MgCl2 + H2

Pb + Zn (NO3) 2 → (the reaction is impossible, since the lead element Pb in the indicated row is after the zinc atom Zn. Hence, it cannot displace it from the solution of its salt).

Cu + 2 AgNO3 → Cu (NO3) 2 + 2 Ag