Coordination Compounds

The intensity of color in a solution is generally associated with the presence of transition metal ions and the extent of transitions or charge transfer transitions they undergo. In the case of manganese compounds, the Mn ion can exhibit different oxidation states, each with distinct colors: : This complex contains ions. typically has a pale pink color due to weak d -d transitions. : This complex contains ions. is not stable in aqueous solution and typically oxidizes water to produce , which is a brown precipitate. The solution would not be intensely colored. : This complex likely contains ions, similar to the first complex, but with different ligands, leading to slightly different colors. : Potassium permanganate contains Mn in the +7 oxidation state, and it is well known for its intense purple color due to strong charge transfer transitions.Among these, (potassium permanganate) gives the most intense color due to the presence of Mn in the +7 oxidation state, which leads to strong charge transfer transitions that result in a deep purple color. Therefore, the answer is:$ $

To determine the number of unpaired electrons in the square planar complex , let's analyze the electronic configuration:Electronic Configuration of Nickel (Ni):Ground state of Ni: Ni in the +2 oxidation state: Effect of the Ligand:Cyanide ( ) is a strong field ligand. It causes significant splitting of the d-orbitals due to its ability to pair electrons efficiently.Geometry and Hybridization:The complex adopts a square planar geometry.In square planar complexes, the hybridization occurs, leading to more pairing of electrons within the d-orbitals.Electron Pairing in d-Orbitals:For with the configuration , strong field ligands like tend to pair up the electrons as much as possible in the 3d orbitals. Conclusion:In this configuration, all the electrons are paired within the d-orbitals.Thus, there are no unpaired electrons in the complex.

The reaction between potassium ferrocyanide and hydrogen peroxide typically involves the oxidation of the ferrocyanide ion to ferricyanide ion ( ).The balanced chemical equation for this reaction is:$ $

A colorless complex typically indicates that there are no d-d transitions in the visible region, meaning the and orbitals are either fully filled or completely empty. i.e., The and orbitals need to either have 0 or 10 electrons in total.On evaluating the options,$ t_{2 g} e_g$ sets are fully filled.

Magnetic Moment CalculationThe magnetic moment of a complex is determined by the number of unpaired electrons using the formula: where is the number of unpaired electrons.Let's evaluate each complex:1. Iron Oxidation State:+2Electronic Configuration of : Ligand Field: is a weak field ligand, so no electron pairing occurs.Unpaired Electrons:4 2. Manganese Oxidation State:+2Electronic Configuration of : Ligand Field: is a weak field ligand, so no electron pairing occurs.Unpaired Electrons:5 3. Manganese Oxidation State:+2Electronic Configuration of : Ligand Field: is a strong field ligand, which causes electron pairing.Unpaired Electrons:1 4. Nickel Oxidation State:0Electronic Configuration of : Ligand Field: is a strong field ligand, which causes electron pairing.Unpaired Electrons:0 ConclusionAmong the complexes given, has a magnetic moment closest to 2 BM (specifically, 1.73 BM), which arises from 1 unpaired electron.

The data required to solve is experimental and has to be memorized from NCERT. The compound is the first compound in the table.