Coordination Compounds

In this question, we are asked to determine the oxidation states of Mn and Cr in their respective ions and their ability to act as reducing or oxidising agents. Both Mn and Cr have a d configuration. Mn has a higher oxidation state compared to Mn , making it an oxidising agent as it is capable of accepting electrons and being reduced to Mn . On the other hand, Cr has a lower oxidation state compared to Cr , making it a reducing agent as it is capable of donating electrons and being oxidised to Cr .

The correct option is (B) : Mn³⁺ is a oxidising agent but Cr²⁺ is an reducing agent

Linkage isomerism arises when a ligand can bind to the metal center through two different atoms. In this case, the two complexes given involve a nitrito ligand, which can bind to the metal center either through the nitrogen (as in ) or the oxygen (as in ), thus creating linkage isomerism. These isomers differ in the donor atom of the ligand.
Therefore, the correct classification for the complexes and is linkage isomers.

The correct option is (E) : linkage isomers

Spectrochemical Series Analysis:

Correct weak-to-strong field order:

Key features:

Halides are weak field (Cl^- weaker than F^-)

H₂O is intermediate field

CN^- is strongest field ligand

Thus, the correct option is (A): .

Crystal Field Theory Comparison:

• Tetrahedral splitting energy (Δ_tet) is smaller than octahedral (Δ_oct)
• Mathematically related as: Δ_tet = (4/9)Δ_oct
• Reason: Fewer ligand interactions and different geometry in tetrahedral

Thus, the correct option is (D): .

Complex Geometry Matching:

a) [Cu(NH₃)₄]²⁺:

• Cu²⁺ typically forms square planar complexes
• Matches with (iii) Square planar

b) [Ag(NH₃)₂]⁺:

• Linear geometry (coordination number 2)
• Matches with (v) Linear

c) Fe(CO)₅:

• Trigonal bipyramidal geometry
• Matches with (iv) Trigonal bipyramidal

d) [Cr(H₂O)₆]³⁺:

• Octahedral geometry (coordination number 6)
• Matches with (ii) Octahedral

e) [NiCl₄]^2-:

• Tetrahedral geometry (with weak field Cl^- ligands)
• Matches with (i) Tetrahedral

Correct Matching: a-(iii), b-(v), c-(iv), d-(ii), e-(i)

Thus, the correct option is (B): a) - (iii); b) - (v); c) - (iv); d) - (ii); e) - (i).

Coordination complexes analysis:

• [NiCl₄]^2-:
  • Weak field ligand (Cl^-)
  • sp³ hybridization → Tetrahedral
• [Ni(CN)₄]^2-:
  • Strong field ligand (CN^-)
  • dsp² hybridization → Square planar

Thus, the correct option is (E): Tetrahedral and square planar, respectively.

Biological compounds analysis:

• (A) Haemoglobin: Contains Fe (iron)
• (B) ATP: Contains P (phosphorus)
• (C) Florigen: Plant hormone (protein, no Mg)
• (D) Ferritin: Iron storage protein
• (E) Chlorophyll: Contains Mg as central atom in porphyrin ring

Thus, the correct option is (E): Chlorophyll.

Complex analysis:

Possible isomerisms:

1. Linkage isomerism: NO₂ can bind through N (nitro) or O (nitrito)
2. Geometrical isomerism: cis/trans arrangements of ligands possible
3. Ionisation isomerism: Cl⁻ could exchange with NO₂⁻ ligand
4. Optical isomerism: Not possible in this tetrahedral complex

Correct combination: The complex exhibits linkage, geometrical, and ionisation isomerism but not optical isomerism.

Thus, the correct option is (B): Linkage isomerism, geometrical isomerism and ionisation isomerism.

Step 1: Inner orbital complexes use low-spin configurations with hybridization, whereas outer orbital complexes use high-spin configurations with hybridization.
Step 2: Fluoride ( ) is a weak field ligand and does not cause strong crystal field splitting. As a result, cobalt in adopts an outer orbital configuration with hybridization.
Step 3: The other complexes:
and involve strong field ligands, leading to inner orbital configurations.
also forms an inner orbital complex.
Step 4: Since is an outer orbital complex, the correct answer is (C).

Step 1: Sodium nitroprusside reacts with sulfur-containing compounds to form a violet complex due to the modification of the iron-cyanide complex.
Step 2: The correct formula of the violet complex formed in the presence of sulfur is , where stands for the nitrosylsulphur ligand.
Step 3: This complex is particularly known for its diagnostic color change when interacting with sulfur.
Step 4: Hence, option (B) correctly represents the composition of the violet complex.

Step 1: The correct IUPAC name reflects the oxidation state of mercury (II) and the coordination of four thiocyanate ions.
Thus, the correct name is Mercury (II) tetrathiocyanato-S-cobaltate (II).