Electrochemistry — Chemistry STD 12 Science — Question

$\left[\mathrm{CoCl}\left(\mathrm{NH}_3\right)_5\right]^{2+}, \quad\left[\mathrm{Co}(\mathrm{CN})_6\right]^{3-} \text {, }$

$(A)$                                        $(B)$

$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5\left(\mathrm{H}_2 \mathrm{O}\right)\right]^{3+}, \quad\left[\mathrm{Cu}\left(\mathrm{H}_2 \mathrm{O}\right)_4\right]^{2+}$

$(C)$                                       $(D)$

The correct order of $A$, $B$, $C$ and $D$ in terms of wavenumber of light absorbed is :

$\begin{align}
   \begin{matrix}
   \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,O\,\,\,\,\,\,\,O  \\
   \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,||\,\,\,\,\,\,\,\,\,||  \\
   H-O-C-C-  \\
\end{matrix}\begin{matrix}
   O\,\,  \\
   ||\,\,\,  \\
   C{{H}_{2}}-C-O-H  \\
\end{matrix} \\ 
  p{{K}_{a}}=2.2\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,p{{K}_{a}}=3.98 \\ 
\end{align}$