Identify the correct statements from the following A. [Fe(C_2O_4)_3]^ 3- is the most stable complex among [Fe(OH)_6]^ 3- , [Fe(C_2O_4)_3]^ 3- and [Fe(SCN)_6]^ 3- B. The stability of [Cu(NH_3)_4]^ 2+ is greater than that of [Cu(en)_2]^ 2+ C. The hybridization of Fe in K_4[Fe(CN)_6] is d^2sp^3 D. [Fe(NO_2)_3Cl_3]^ 3- exhibits linkage isomerism E. NO_2^- and SCN^- ligands are NOT ambidentate ligands Choose the correct answer from the options given below :
C. A, C and D only
Statement A is correct. The oxalate ion (C_2O_4^ 2- ) is a bidentate ligand and forms chelate rings with the central metal ion. Due to the chelate effect, [Fe(C_2O_4)_3]^ 3- is more stable than complexes formed by monodentate ligands like [Fe(OH)_6]^ 3- and [Fe(SCN)_6]^ 3- . Statement B is incorrect. Ethylenediamine (en) is a bidentate ligand and forms chelate rings, whereas NH_3 is a monodentate ligand. Therefore, [Cu(en)_2]^ 2+ is more stable than [Cu(NH_3)_4]^ 2+ due to the chelate effect. Statement C is correct. In K_4[Fe(CN)_6], the oxidation state of Fe is +2, which corresponds to a 3d^6 configuration. Since CN^- is a strong field ligand, it causes the pairing of electrons in the 3d orbitals, leaving two inner 3d orbitals empty. Thus, the hybridization is d^2sp^3. Statement D is correct. The NO_2^- ligand is an ambidentate ligand, meaning it can coordinate to the metal center through either the nitrogen atom or the oxygen atom. Therefore, [Fe(NO_2)_3Cl_3]^ 3- can exhibit linkage isomerism. Statement E is incorrect. Both NO_2^- and SCN^- are ambidentate ligands. NO_2^- can bind through N or O, and SCN^- can bind through S or N. Therefore, the correct statements are A, C, and D. Answer: A, C and D only
Related: Chemistry — Coordination Compounds · All PYQ Banks