Self-exchange electron transfer is fastest in · ABC26IN0141
Subject: Inorganic Chemistry · Chapter: Coordination Chemistry · Topic: Electron Transfer Redox · Exam: CSIR NET 2020 · Marks: 2 · Difficulty: Medium
Self-exchange electron transfer is fastest in
(a)$[\mathrm{Ru(NH_3)_6}]^{2+/3+}$
(b)$[\mathrm{Co(NH_3)_6}]^{2+/3+}$
(c)$[\mathrm{Cr(OH)_6}]^{2+/3+}$
(d)$[\mathrm{Fe(OH_2)_6}]^{2+/3+}$
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
[Ru(NH₃)₆]²⁺/³⁺ transfers the electron t₂g → t₂g (π*/π*) with almost no change in metal–ligand distances, so self-exchange is fast (~10⁴ M⁻¹ s⁻¹). The Co, Cr and Fe couples change e_g occupancy and are much slower (a).