Question

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

• A. $\left[ PtCl _{2}\left( NH _{3}\right)_{4}\right] Br _{2}$ and $\left[ PtBr _{2}\left( NH _{3}\right)_{4}\right] Cl _{2}$
• B. $\left[ Pt ( OH )_{2}\left( NH _{3}\right)_{4}\right] SO _{4}$ and $\left[ PtSO _{4}\left( NH _{3}\right)_{4}\right]( OH )_{2}$
• C. $K _{3}\left[ Fe ( CN )_{2}\right]$ and $K _{4}\left[ Fe ( CN )_{6}\right]$
• D. $\left[ Co \left( NH _{3}\right)_{5} Br \right] SO _{4}$ and $\left[ Co \left( NH _{3}\right)_{5} SO _{4}\right] Br$

Answer 1

Answer: (D)

$\left[ Co \left( NH _{3}\right)_{5} Br \right] SO _{4}$ and $\left[ Co \left( NH _{3}\right)_{5} SO _{4}\right] Br$ are ionisation

isomers but their molar conductivity is different due to different magnitude of charge on the cation and anion respectively as follows $\left[ Co \left( NH _{3}\right)_{5} Br \right] SO _{4} \rightarrow\left[ Co \left( NH _{3}\right)_{5} Br \right]^{2+}+ SO _{4}^{2-}$

$\left[ Co \left( NH _{3}\right)_{5} SO _{4}\right] Br \rightarrow\left[ Co \left( NH _{3}\right)_{5} SO _{4}\right]^{+}+ Br ^{-}$