Question

The UV-visible spectrum of [Ni(en)\(_3\)]\(^{2+}\) (en = ethylenediamine) shows absorbance maxima at 11200 cm\(^{-1}\), 18350 cm\(^{-1}\), and 29000 cm\(^{-1}\). 

[Given: Atomic number of Ni = 28] The correct match(es) between absorbance maximum and electronic transition is/are

• (a) $\rightarrow$ (ii)
• (b) $\rightarrow$ (i)
• (a) $\rightarrow$ (iii)
• (c) $\rightarrow$ (iii)

Hint:

For octahedral d\(^8\) complexes, there are three spin-allowed d-d transitions. The energy order typically follows the increasing energy of the excited states in the crystal field splitting diagram. Strong field ligands increase the splitting energy (\(\Delta_o\)), leading to higher energy transitions.

Answer 1

The Correct Option is A, B, D

• (a) → (ii)
• (b) → (i)
• (c) → (iii)

 

This corresponds to options (A), (B), and (D).