Question

Cerium (Z = 58) is an important member of the Lanthanoid. Which of the following statement is incorrect about it?

• A. The +3 oxidation state of cerium is more stable than the +4 oxidation state
• B. The common oxidation states of cerium are +3and +4
• C. Cerium (IV) acts as an oxidizing agent
• D. The +4 oxidation state of cerium is not known in solutions

Answer 1

The correct option is D The +4 oxidation state of cerium is not known in solutions

For Cerium the +3 oxidation state is more stable than +4.

The formation of $C{e}^{4+}$ is favoured by its noble gas configuration, but it is a strong oxidant reverting to the common +3 state.

The $E^o$ value for $C{e}^{4+}$/ $C{e}^{3+}$ is + 1.74 V which suggests that it can oxidise water.