# What is the oxidizing agent of f this chemical process? Fe + Cu(NO_3)_2 → Fe(NO_3)_2 + Cu

An oxidizing agent formally ACCEPTS electrons. Therefore, here, the agent is $C {u}^{2 +}$.
In your equation, you have an electron-rich, elemental metal, i.e. $F e$, and this acts as a reducing agent. On the other hand, you have a dicationic metal ion, $C {u}^{2 +}$, which is an electron sink. Since $C {u}^{2 +}$ is reduced by accepting electrons; the oxidizing agent is this ion.