Question

A coordination compound of iron is P that has the coordination number of iron 6 and oxidation number of iron is +3. If compound P shows geometrical as well as optical isomerism. 1 mol of compound P form 4 mole of ions when dissolved in water. The compound P may be?

• A. $\left[Fe\right(H_{2}O{)}_2\left(en{)}_2\right]C{l}_3$
• B. $\left[Fe\right(H_{2}O{)}_4\left(en\right)]C{l}_2$
• C. $\left[Fe\right(H_{2}O{)}_4\left(N{H}_3{)}_2\right]C{l}_3$
• D. $\left[Fe\right(H_{2}O{)}_4\left(en\right)]C{l}_3$

Answer 1

The correct option is A $\left[Fe\right(H_{2}O{)}_2\left(en{)}_2\right]C{l}_3$

Co-ordination number of iron is $6$. Oxidation number of iron is $+3$. $1$ mole of compound form $4$ mole of ions. Considering the above criteria only option A i.e. $\left[Fe\right(H_{2}O{)}_2\left(en{)}_2\right]C{l}_3$ and option C i.e. $\left[Fe\right(H_{2}O{)}_4\left(N{H}_3{)}_2\right]C{l}_3$ are possible.

(Refer to Image 1)

Optical isomers of A

(Refer to Image 2)

Geometrical isomers of A

But C has no optical isomerism. The compound P will be $\left[Fe\right(H_{2}O{)}_2\left(en{)}_2\right]C{l}_3$ .