Question

Given below are 4 statements. Two of these are correct statements. Identify them.

• A. Co\(^{2+}\) is easily oxidised to Co\(^{3+}\) in the presence of a strong ligand like CN\(^{-}\)
• B. \([Fe(CN)_6]^{4-}\) is an octahedral complex ion which is paramagnetic in nature.
• C. Removal of H\(_2\)O molecules from \([Ti(H_2O)_6]Cl_3\) on strong heating converts it to a colourless compound.
• D. Crystal Field splitting in Octahedral and Tetrahedral complexes is given by the equation \(\Delta_0 = 4/9 \Delta_t\)

Hint:

Remember, ligands like CN\(^-\) can significantly stabilize higher oxidation states, making such oxidation easier for metals like Co. Also, always check the geometry of the complex to determine if it’s paramagnetic or diamagnetic based on electron pairing.

Answer 1

The Correct Option is A

- Statement A: Co\(^{2+}\) is indeed easily oxidized to Co\(^{3+}\) in the presence of strong ligands like CN\(^-\) due to the ligand's ability to stabilize the higher oxidation state, making it an accurate statement.
- Statement B: The complex \([Fe(CN)_6]^{4-}\) is a low-spin octahedral complex and, due to the pairing of electrons, it is actually diamagnetic, not paramagnetic. Therefore, this statement is incorrect.
- Statement C: Removal of H\(_2\)O molecules from \([Ti(H_2O)_6]Cl_3\) on strong heating typically converts the compound to a colourless form, making this statement true.
- Statement D: The formula \(\Delta_0 = 4/9 \Delta_t\) is not a general expression for crystal field splitting. Instead, it is a specific case for a Tetrahedral field, and therefore, this statement is incorrect.
Thus, the correct statements are A and C.