JEE Chemistry 2023 Question with Solution

Given: The species are $Sm^{2+}$, $Ce^{2+}$, $Ce^{4+}$ and $Tb^{4+}$.

Find: Which among them are good oxidizing agents.

A good oxidizing agent readily accepts electrons to attain a more stable oxidation state.

From the explanation:

• $Ce^{4+}$ acts as a good oxidizing agent because it readily accepts electrons to attain the more stable $Ce^{3+}$ configuration.
• $Tb^{4+}$ also acts as a good oxidizing agent because it gets reduced to the more stable $Tb^{3+}$ configuration.
• $Sm^{2+}$ and $Ce^{2+}$ are reducing agents because they tend to lose electrons to attain stable configurations.

Thus, the good oxidizing agents are $Ce^{4+}$ and $Tb^{4+}$. Therefore, the correct option is B.