Import Question JSON

$\text{HINT: } [\text{Cr} (\text{NH}_3)_6]^{3+} \text{ is a coloured complex.}$ $\text{Explanation:}$ $\text{By absorption of visible light, it simply means that the compound shows colour and is visible to us.}$ $\text{Also, we know that the compounds with unpaired electrons show d-d transition.}$ $\text{Hence, those metal complexes in which the d-subshell is incomplete are expected to absorb visible light.}$ $\text{(b) In } [\text{Ti} (\text{en})_2 (\text{NH}_3)_2]^{4+}, \text{ O.S. of Ti is +4.}$ $\text{Ti}^{4+} = [\text{Ar}] \ 3d^0 \ 4s^0$ $\text{It will also not absorb visible light as it has no electrons in d subshell.}$ $\text{(c) In } [\text{Cr} (\text{NH}_3)_6]^{3+}, \text{ O.S. of Cr is +3}$ $\text{Cr}^{3+} = [\text{Ar}] \ 3d^3 \ 4s^0$ $\text{Because of the presence of three unpaired electrons which will occupy lower } t_{2g} \text{ set of orbitals can easily undergo transition to higher } e_g \text{ set showing transition and hence colour i.e. it is expected to absorb visible light.}$ $\text{(d) In } [\text{Zn} (\text{NH}_3)_6]^{2+}, \text{ O.S. of Zn is +2.}$ $\text{Zn}^{2+} = [\text{Ar}] \ 3d^{10} \ 4s^0$ $[\text{Zn} (\text{NH}_3)_6]^{2+} = [\text{Ar}] \ 3d^{10}$ $\text{As the d subshell is completely filled, there is no room for transition to occur and no transition can occur resulting in no absorption of visible light.}$