Q31 / 160 · TS EAMCET 2024 (10 May Shift 2) · Chemistry
Arrange the following in increasing order of their crystal field splitting energy
I. $\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$
II. $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
III. $\left[\mathrm{Co}(\mathrm{CN})_6\right]^{3-}$
IV: $\left[\mathrm{CoF}_6\right]^{3-}$
IV: $\left[\mathrm{CoF}_6\right]^{3-}$
- AI $ \lt $ II $ \lt $ III $ \lt $ IV
- Correct answerBIV $ \lt $ I $ \lt $ II $ \lt $ III
- CI $ \lt $ III $ \lt $ II $ \lt $ IV
- DIV $ \lt $ II $ \lt $ I $ \lt $ III
Solution
More the strong field ligand more will be the crystal field splitting energy.
According to electrochemical series order of field strength.
$\mathrm{CN}\gt\mathrm{NH}_3\gt\mathrm{H}_2 \mathrm{O}\gt\mathrm{F}$
So. crystal field splitting energy (CFSE) order.
III $\gt$ II $\gt$ I $\gt$ IV.
Hence, the correct answer is option: 'B'.