Three complexes,$[CoCl(NH_3)_5]^{2+} (I)$,$[Co(NH_3)_5H_2O]^{3+} (II)$ and $[Co(NH_3)_6]^{3+} (III)$ absorb light in the visible region. The correct order of the wavelength of light absorbed by them is

Which of the following are true about the energy of the given d-orbitals of a tetrahedral complex?
$A$. $d_{xy} = d_{xz} > d_{x^2-y^2}$
$B$. $d_{xy} = d_{yz} > d_{z^2}$
$C$. $d_{x^2-y^2} > d_{z^2} > d_{xz}$
$D$. $d_{x^2-y^2} = d_{z^2}$
Choose the correct answer from the given below:

Which of the following sequences is correct regarding the field strength of ligands as per the spectrochemical series?

$CuSO_4 \cdot 5 H_2O$ is blue in colour while $CuSO_4$ is colourless. Why?

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

The hexaquo manganese $(II)$ ion contains five unpaired electrons,while the hexacyano manganese $(II)$ ion contains only one unpaired electron. Explain using Crystal Field Theory.