Why is the solution of (NH4)2[Ce(NO3)6] used as an oxidizing agent? [closed]

In an MCQ, the correct statement regarding the abovementioned compound is that its solution is used as an oxidizing agent. I do not understand why that is so.

• calculate the oxidation state of Ce in the compound. – M. Farooq Nov 23 '19 at 5:49
• I think it's +4. Which means it has achieved Xe configuration. – Novice chemist Nov 23 '19 at 9:47

Most lanthanides display stability in their +3 oxidation states. Cerium does the same, which is why it has a very high reduction potential. The reduction potential for the $$\ce{Ce^{4+}|Ce^{3+}}$$ couple is 1.61 V (for comparison, $$\ce{Cl2}$$ has a potential of 1.32 V)
Cerium in the form of ceric ammonium nitrate is also quite stable compared to other oxidizing agents and can be stored on the shelf for a longish period of time. It's also quite usable: the bright orange colour is decolourized to a pale yellow on reduction of $$\ce{Ce^{4+}}$$. This is why it's used as a common oxidizing agent.