Subject: Inorganic Chemistry · Chapter: Lanthanides and Actinides · Topic: Magnetic Properties 4f · Exam: CSIR-NET 2015 · Marks: 2 · Difficulty: Medium
Consider the following statements for $\left(\mathrm{NH}_{4}\right)_{2}\left[\mathrm{Ce}\left(\mathrm{NO}_{3}\right)_{6}\right]$ (Z)(A) Coordination number of Ce is 12(B) Z is paramagnetic(C) Z is an oxidising agent(D) Reaction of $\mathrm{Ph_3PO}$ with Z gives a complex having coordination number 10 for Ce.The correct statements are
(a)A, B and C
(b)B, A and D
(c)B, C and D
(d)A, C and D
Answer
Answer (as printed): D
Explanation
$(\mathrm{NH_4})_2[\mathrm{Ce(NO_3)_6}]$ (Z).(1) $\mathrm{NO_3^{-}}$ behaves as a bidentate ligand. Hence, C.N. $=12$.(2) $\mathrm{Ce^{4+}}$ has no unpaired electron, hence diamagnetic, not paramagnetic.(3) $\mathrm{Ce^{4+}}$ has a higher oxidation state, hence behaves as an oxidising agent.(4) $(\mathrm{NH_4})_2[\mathrm{Ce(NO_3)_6}]$ on reaction with $\mathrm{Ph_3PO}$ gives $[\mathrm{Ce(NO_3)_4(Ph_3PO)_2}]$ having C.N. $=10$. Hence, correct statement.$\mathrm{OPPh_3}$ = monodentate ligand; $\mathrm{NO_3}$ = bidentate.