Question

Which of the following pairs of complexes are isomeric with each other but their aqueous solutions exhibit different molar conductivities?

• A. $\left[PtC{l}_2{\left(N{H}_3\right)}_4\right]B{r}_2$ and $\left[PtB{r}_2{\left(N{H}_3\right)}_4\right]C{l}_2$
• B. $\left[Pt(OH{)}_2{\left(N{H}_3\right)}_4\right]S{O}_4$ and $\left[PtS{O}_4{\left(N{H}_3\right)}_4\right](OH{)}_2$
• C. $K_3\left[Fe(CN{)}_2\right]$ and $K_4\left[Fe(CN{)}_6\right]$
• D. $\left[Co{\left(N{H}_3\right)}_{5}Br\right]S{O}_4$ and $\left[Co{\left(N{H}_3\right)}_{5}S{O}_4\right]Br$

Answer 1

Answer: (D)

$\left[Co{\left(N{H}_3\right)}_{5}Br\right]S{O}_4$ and $\left[Co{\left(N{H}_3\right)}_{5}S{O}_4\right]Br$ are ionisation

isomers but their molar conductivity is different due to different magnitude of charge on the cation and anion respectively as follows $\left[Co{\left(N{H}_3\right)}_{5}Br\right]S{O}_4\to {\left[Co{\left(N{H}_3\right)}_{5}Br\right]}^{2+}+S{O}_4^{2-}$

$\left[Co{\left(N{H}_3\right)}_{5}S{O}_4\right]Br\to {\left[Co{\left(N{H}_3\right)}_{5}S{O}_4\right]}^{+}+B{r}^{-}$