Question

The crystal field-splitting for $C{r}^{3+}$ ion in octahedral field increases for ligands $I^{-},H_{2}O,N{H}_3,C{N}^{-}$ and the order is:

• A. $I^{-}<H_{2}O<N{H}_3<C{N}^{-}$
• B. $C{N}^{-}<I^{-}<H_{2}O<N{H}_3$
• C. $C{N}^{-}<N{H}_3<H_{2}O<I^{-}$
• D. $N{H}_3<H_{2}O<I^{-}<C{N}^{-}$

Answer 1

The correct option is A $I^{-}<H_{2}O<N{H}_3<C{N}^{-}$

The crystal field-splitting for $C{r}^{3+}$ ion in octahedral field increases for ligands $I^{-},H_{2}O,N{H}_3,C{N}^{-}$ and the order is $I^{-}<H_{2}O<N{H}_3<C{N}^{-}$ This is in accordance with spectrochemical series. The power for splitting the metal d orbitals is higher for strong ligands than for weaker ligands. Spectrochemical series arranges the ligands based on their splitting powers.