The degeneracy of $d-$orbitals is lost under:
$I$. Strong field ligand
$II$. Weak field ligand
$III$. Mixed field ligand
$IV$. Chelated ligand field
Choose the correct code:

If $[Cu(H_{2}O)_{4}]^{2+}$ absorbs light of wavelength $600 \ nm$ for $d-d$ transition,then the value of octahedral crystal field splitting energy for $[Cu(H_{2}O)_{6}]^{2+}$ will be $..... \times 10^{-21} \ J$. (Nearest Integer)
(Given: $h = 6.63 \times 10^{-34} \ Js$ and $c = 3.08 \times 10^{8} \ ms^{-1}$)

$A$ $[M(H_2O)_6]^{2+}$ complex typically absorbs at around $600 \ nm$. It is allowed to react with ammonia to form a new complex $[M(NH_3)_6]^{2+}$ that should have absorption at ....... $nm$.

Arrange the following in increasing order of their crystal field splitting energy:
$I. [Co(H_2O)_6]^{3+}$
$II. [Co(NH_3)_6]^{3+}$
$III. [Co(CN)_6]^{3-}$
$IV. [CoF_6]^{3-}$

In potassium ferrocyanide,there are $..........$ pairs of electrons in the $t_{2g}$ set of orbitals.

Using crystal field theory,draw energy level diagrams,write the electronic configuration of the central metal atom/ion,and determine the magnetic moment value for the following:
$(i)$ $[CoF_{6}]^{3-}, [Co(H_{2}O)_{6}]^{2+}, [Co(CN)_{6}]^{3-}$
$(ii)$ $[FeF_{6}]^{3-}, [Fe(H_{2}O)_{6}]^{2+}, [Fe(CN)_{6}]^{4-}$