Question

Among the following the most stable complex is

• A. $\left[Fe\right(H_{2}O{)}_6{]}^{3+}$
• B. $\left[Fe\right(CN{)}_6{]}^{3-}$
• C. $\left[Fe\right(C_2{O}_4{)}_3{]}^{3-}$
• D. $[FeC{l}_6{]}^{3-}$

Answer 1

The correct option is C $\left[Fe\right(C_2{O}_4{)}_3{]}^{3-}$

In the ideas on chelation, we just saw that if a compound has chelation it is going to be a lot more stable. Among the options, all the other ions are monodentate barring $\left[Fe\right(C_2{O}_4{)}_3{]}^{3-}$. The oxalate anion will form a chelate with iron and hence would be more stable. Simple idea isn't it?