Paper: CSIR-NET June 2016 · Subject: Inorganic Chemistry · Chapter: Coordination Chemistry · Topic: Coordination Chemistry – General · Marks: 2 · Difficulty: Medium
$\left[\mathrm{Ni}^{\mathrm{II}} \mathrm{L}_{6}\right]^{\mathrm{n+\ or\ n-}}$ shows absorption bands at 8500, 15400, and $26000\ \mathrm{cm}^{-1}$ whereas $\left[\mathrm{Ni}^{\mathrm{II}} \mathrm{L'}_{6}\right]^{\mathrm{n+\ or\ n-}}$ at 10750, 17500 and $28200\ \mathrm{cm}^{-1}$. L and L' are respectively
(a)$\mathrm{OH}^{-}$ and $\mathrm{N}_{3}^{-}$
(b)$\mathrm{Cl}^{-}$ and $\mathrm{I}^{-}$
(c)$\mathrm{NCS}^{-}$ and $\mathrm{RCO}_{2}^{-}$
(d)$\mathrm{H}_{2} \mathrm{O}$ and $\mathrm{NH}_{3}$
Answer
Answer: D ✓ checked by 4AB · confidence high
The source book printed no answer; this one was worked out and checked — see the explanation.
Explanation
The first band is Δ₀: 8500 cm⁻¹ is [Ni(H₂O)₆]²⁺ and 10750 cm⁻¹ is [Ni(NH₃)₆]²⁺, the classic pair from the spectrochemical series.