Question

One among the lanthanoids, Ce (III) can be easily oxidised to Ce (IV). Explain.

Answer 1

1. Ce (III) has an electronic configuration [Xe] 4f¹ and can lose one more electron to attain a stable noble gas-like configuration in Ce (IV).
2. Ce (IV) has a stable electronic configuration similar to a noble gas, making Ce (III) easy to oxidize to Ce (IV).
3. The Ce (IV) ion is a strong oxidizing agent and easily gets reduced to Ce (III), showing that Ce (III) easily oxidizes to Ce (IV).
4. Unlike other lanthanoids, Ce can exist stably in +4 state due to the extra stability and energy factors related to its electronic configuration.
5. This property is unique as most lanthanoids prefer the +3 oxidation state; the ability of Ce to attain the +4 state is why compounds like Ce(SO₄)₂ are commonly used in volumetric analysis.

Hence, Ce (III) can be easily oxidized to Ce (IV) due to the stability and favorable energy of the +4 state with noble gas configuration.