Answer ALL questions in this section. 35 marks) 1. Shown below are the thermodynamic data of five octahedral iron comple
Posted: Tue May 17, 2022 11:25 am
Answer ALL questions in this section. 35 marks) 1. Shown below are the thermodynamic data of five octahedral iron complexes at 298 K. All the ligands are charge-neutral. AH/kJmol-1 log B AS/Jmol 'K- -36 _92.7 -50 / [Fe(L1).]2+ [Fe(L2).]2+ [Fe(L3)3]2+ [Fe(L1)6]3+ [Fe(L2).]3+ -66.3 -68.9 -3 / / / 11.2 13.6 / (a) The magnetic moment of [Fe(L1)6]2+ is 4.89 BM. Provide a simplified orbital diagram showing the configuration of d electrons and calculate the crystal field stabilization energy for [Fe(L1)6]2+. (3 marks) (b) Calculate log B for [Fe(L1).]2+, [Fe(L2)6]2+ and [Fe(L3)3]2+. (3 marks) (c) How do you explain the different ß values for [Fe(L2)6]2+ and [Fe(L3)3]2+? (4 marks) (d) The reduction potential of [Fe(H20)6]3+/2+ is +0.77 V (vs. NHE). Calculate the reduction potential of [Fe(L1).]3+/2+ and rationalize your answer. (6 marks) (e) Predict, with explanation, whether the reduction potential of [Fe(L2)6]3+/2+ would be greater or smaller than +0.77 V (vs. NHE) and compare the hard-soft acid- base properties of L1 and 12