Question:
Given below are two statements :
Statement I : The $\mathrm{E}^{\circ}$ value of $\mathrm{Ce}^{4+} / \mathrm{Ce}^{3+}$ is $+1.74 \mathrm{~V}$.
Statement II : Ce is more stable in $\mathrm{Ce}^{4+}$ state than $\mathrm{Ce}^{3+}$ state.
In the light of the above statements, choose the most appropriate answer from the options given below :
Correct Option: , 4
Solution:
The $\mathrm{E}^{\circ}$ value for $\mathrm{Ce}^{4+} / \mathrm{Ce}^{3+}$ is $+1.74 \mathrm{~V}$ because the most stable oxidation state of lanthanide series elements is $+3$.
It means $\mathrm{Ce}^{3+}$ is more stable than $\mathrm{Ce}^{4+}$