Question

Given below are two statements : Statement I : CeO$_2$ can be used for oxidation of aldehydes and ketones. Statement II : Aqueous solution of EuSO$_4$ is a strong reducing agent. In the light of the above statements, choose the correct answer :

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Hint:

For Lanthanides: $Ce^{4+}$ is a strong oxidant (wants to reach $+3$), while $Eu^{2+}$ is a strong reductant (wants to reach $+3$). $+3$ is the "safe haven" oxidation state for the f-block.

Answer 1

The Correct Option is A

Step 1: Cerium in $CeO_2$ is in the $+4$ oxidation state. $Ce^{4+}$ is a well-known analytical oxidizing agent (Ceric ammonium nitrate) used for organic oxidations. Statement I is true.
Step 2: Europium commonly exists as $Eu^{2+}$ in $EuSO_4$. The most stable state for lanthanides is $+3$.
Step 3: $Eu^{2+}$ tends to lose an electron to become $Eu^{3+}$, thus acting as a strong reducing agent. Statement II is true.