Question

The number of optical isomers exhibited by the iron complex (A) obtained from the following reaction is ______ $ FeCl_3 + KOH + H_2C_2O_4 \rightarrow A $

Hint:

For \( [M(AA)_3] \) type complexes, where AA is a symmetrical bidentate ligand, the complex is chiral and exists as two optical isomers (d and l forms).

Answer 1

Correct Answer: 2

The reaction involves FeCl₃, KOH, and H₂C₂O₄, producing a complex iron compound, denoted as A. The objective is to determine the number of optical isomers.

Step 1: Determine the Iron Complex

Reaction of FeCl₃ with oxalic acid (H₂C₂O₄) in KOH yields potassium ferrioxalate, K₃[Fe(C₂O₄)₃].

Step 2: Identify the Coordination Sphere

The iron (Fe) in K₃[Fe(C₂O₄)₃] has a coordination number of 6, as the oxalate ligand (C₂O₄) is bidentate.

Step 3: Understand Optical Isomerism

Optical isomerism arises in complexes where ligand arrangements can form non-superimposable mirror images. The oxalate ligands in K₃[Fe(C₂O₄)₃] create a chiral center around the metal, enabling this.

Step 4: Identify and Count the Optical Isomers

K₃[Fe(C₂O₄)₃] exists as two non-superimposable mirror images, or enantiomers, designated as 'Δ' and 'Λ' forms, resulting in 2 optical isomers.

Conclusion

There are 2 optical isomers. This result aligns with the specified range of 2 to 2.