Match the complexes given in column I with the electronic transitions (mainly responsible for their colours)… · ABC26IN0110

Subject: Inorganic Chemistry · Chapter: Coordination Chemistry · Topic: Electron Transfer Redox · Exam: CSIR NET 2015 · Marks: 2 · Difficulty: Medium

Match the complexes given in column I with the electronic transitions (mainly responsible for their colours) listed in column II
Column-IColumn-II
(I) Fe(II)-protoporphyrin IX(A) $\pi \rightarrow \pi^{*}$
(II) $\left[\mathrm{Mn}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{Cl}_{2}$(B) spin allowed d-d
(III) $\left[\mathrm{Co}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{Cl}_{2}$(C) spin forbidden $\mathrm{d} \rightarrow \mathrm{d}$
(D) $\mathrm{M} \rightarrow \mathrm{L}$ charge transfer
The correct answer is:
(a)I-A, II-C and III-B
(b)I-D, II-B and III-C
(c)1-A, II-C and III-D
(d)I-A, II-B and III-C
Answer
Answer: A ✓ checked by 4AB · confidence medium

The option list is shifted in the scan; the correct match is I-A, II-C, III-B.

Explanation
Fe(II) protoporphyrin IX (heme) owes its colour to the intense π→π* bands of the porphyrin (A). [Mn(H₂O)₆]²⁺ is high-spin d⁵, where every d–d transition is spin-forbidden (C), which is why it is so pale. [Co(H₂O)₆]²⁺ (d⁷) shows ordinary spin-allowed d–d bands (B).

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