Increasing order of crystal field splitting power of following ligands will be:

(A) $CN^-$
(B) $Cl^-$
(C) $F^-$
(D) $H_2O$

Choose the correct answer from the options given below:

(B) < (C) < (D) < (A)

The correct answer is Option (4) → (B) < (C) < (D) < (A)

Crystal Field Splitting Power of ligands follows the spectrochemical series, which orders ligands from weak field (low splitting) to strong field (high splitting).

Weak field ligands → small splitting

Strong field ligands → large splitting

I⁻ < Br⁻ < Cl⁻ < F⁻ < H₂O < NH₃ < CN⁻ < CO

Here’s the relevant portion of the spectrochemical series (in increasing order of crystal field splitting):

Cl⁻ < F⁻ < H₂O < CN⁻

So, from weakest to strongest field ligand:

• (B) Cl⁻

• (C) F⁻

• (D) H₂O

• (A) CN⁻

Thus, the increasing order of crystal field splitting power is:(B) < (C) < (D) < (A)