Match List-I with List-II: List-I (Complex) (a) $[\mathrm{Co}(\mathrm{NH}{}_3){}_5(\mathrm{NO}{}_2)]\mathrm{Cl}{}_2$ (b) $[\mathrm{Co}(\mathrm{NH}{}_3){}_5(\mathrm{SO}{}_4)]\mathrm{Br}$ (c) $[\mathrm{Co}(\mathrm{NH}{}_3){}_6][\mathrm{Cr}(\mathrm{CN}){}_6]$ (d) $[\mathrm{Co}(\mathrm{H}{}_2\mathrm{O}){}_6]\mathrm{Cl}{}_3$ List-II (Type of isomerism) (i) Solvate isomerism (ii) Linkage isomerism (iii) Ionization isomerism (iv) Coordination isomerism Choose the correct option:

Solution & Explanation

\textbf{Answer:} (D) (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i). \textbf{Solution:} (a) $[\mathrm{Co}(\mathrm{NH}{}_3){}_5(\mathrm{NO}{}_2)]\mathrm{Cl}{}_2$: the $\mathrm{NO}{}_2$ group is ambidentate (can bind through N as nitro –$\mathrm{NO}{}_2$ or through O as nitrito –ONO) $\Rightarrow$ \textbf{linkage isomerism} (ii). (b) $[\mathrm{Co}(\mathrm{NH}{}_3){}_5(\mathrm{SO}{}_4)]\mathrm{Br}$: the $\mathrm{SO}{}_4$ inside and $\mathrm{Br}{}^{-}$ outside the sphere can interchange $\Rightarrow$ \textbf{ionization isomerism} (iii). (c) $[\mathrm{Co}(\mathrm{NH}{}_3){}_6][\mathrm{Cr}(\mathrm{CN}){}_6]$: both cation and anion are complex ions, so ligands can be distributed differently between the two metal centres $\Rightarrow$ \textbf{coordination isomerism} (iv). (d) $[\mathrm{Co}(\mathrm{H}{}_2\mathrm{O}){}_6]\mathrm{Cl}{}_3$: water can move between the coordination sphere and the lattice $\Rightarrow$ \textbf{solvate (hydrate) isomerism} (i). Thus (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i), option (D).